Migration tool: sequential → hash IDs

Create migration tool to convert existing sequential-ID databases to hash-ID format.

## Command: bd migrate --hash-ids

```bash
bd migrate --hash-ids [--dry-run]
```

## Migration Process

### 1. Backup Database
```bash
cp .beads/beads.db .beads/beads.db.backup-1761798384
echo "✓ Backup created: .beads/beads.db.backup-1234567890"
```

### 2. Generate Hash IDs for Existing Issues
```go
func migrateToHashIDs(db *SQLiteStorage) error {
    // Read all issues
    issues, err := db.ListIssues(ctx, ListOptions{Status: "all"})

    // Generate mapping: old ID → new hash ID
    mapping := make(map[string]string)
    for _, issue := range issues {
        hashID := GenerateHashID(
            issue.Title,
            issue.Description,
            issue.CreatedAt,
            db.workspaceID,
        )
        mapping[issue.ID] = hashID
    }

    // Detect hash collisions (extremely rare)
    if hasCollisions(mapping) {
        return fmt.Errorf("hash collision detected, aborting")
    }

    return nil
}
```

### 3. Update Database Schema
```sql
-- Add alias column
ALTER TABLE issues ADD COLUMN alias INTEGER UNIQUE;

-- Populate aliases from old IDs
UPDATE issues SET alias = CAST(SUBSTR(id, 4) AS INTEGER)
  WHERE id LIKE 'bd-%' AND SUBSTR(id, 4) GLOB '[0-9]*';

-- Create new issues_new table with hash IDs
CREATE TABLE issues_new (
    id TEXT PRIMARY KEY,  -- Hash IDs now
    alias INTEGER UNIQUE,
    title TEXT NOT NULL,
    -- ... rest of schema
);

-- Copy data with ID mapping
INSERT INTO issues_new SELECT
    <new_hash_id>,  -- From mapping
    alias,
    title,
    -- ...
FROM issues;

-- Drop old table, rename new
DROP TABLE issues;
ALTER TABLE issues_new RENAME TO issues;
```

### 4. Update Dependencies
```sql
-- Update depends_on_id using mapping
UPDATE dependencies
SET issue_id = <new_hash_id>,
    depends_on_id = <new_depends_on_hash_id>
FROM mapping;
```

### 5. Update Text References
```go
// Update all text fields that mention old IDs
func updateTextReferences(db *SQLiteStorage, mapping map[string]string) error {
    for oldID, newID := range mapping {
        // Update description, notes, design, acceptance_criteria
        db.Exec(`UPDATE issues SET
            description = REPLACE(description, ?, ?),
            notes = REPLACE(notes, ?, ?),
            design = REPLACE(design, ?, ?),
            acceptance_criteria = REPLACE(acceptance_criteria, ?, ?)
        `, oldID, newID, oldID, newID, oldID, newID, oldID, newID)
    }
}
```

### 6. Export to JSONL
```bash
bd export  # Writes hash IDs to .beads/issues.jsonl
git add .beads/issues.jsonl
git commit -m "Migrate to hash-based IDs"
```

## Output
```bash
$ bd migrate --hash-ids
Migrating to hash-based IDs...
✓ Backup created: .beads/beads.db.backup-1730246400
✓ Generated 150 hash IDs
✓ No hash collisions detected
✓ Updated issues table schema
✓ Updated 150 issue IDs
✓ Updated 87 dependencies
✓ Updated 234 text references
✓ Exported to .beads/issues.jsonl
✓ Migration complete!

Next steps:
  1. Test: bd list, bd show #1, etc.
  2. Commit: git commit -m "Migrate to hash-based IDs"
  3. Push: git push origin main
  4. Notify collaborators to pull and re-init
```

## Dry Run Mode
```bash
$ bd migrate --hash-ids --dry-run
[DRY RUN] Would migrate 150 issues:
  bd-1c63eb84   → bd-af78e9a2  (alias: #1)
  bd-9063acda   → bd-e5f6a7b8  (alias: #2)
  ...
  bd-150 → bd-9a8b7c6d  (alias: #150)

[DRY RUN] Would update:
  - 150 issue IDs
  - 87 dependencies
  - 234 text references in descriptions/notes

No changes made. Run without --dry-run to apply.
```

## Files to Create
- cmd/bd/migrate.go (new command)
- internal/storage/sqlite/migrations/hash_ids.go

## Testing
- Test migration on small database (10 issues)
- Test migration on large database (1000 issues)
- Test hash collision detection (inject collision artificially)
- Test text reference updates
- Test rollback (restore from backup)
- Test migrated database works correctly

## Rollback Procedure
```bash
# If migration fails or has issues
mv .beads/beads.db.backup-1234567890 .beads/beads.db
bd export  # Restore JSONL from backup DB
```

## Multi-Clone Coordination
**Important**: All clones must migrate before syncing:

1. Coordinator sends message: "Migrating to hash IDs on 2025-10-30 at 10:00 UTC"
2. All collaborators pull latest changes
3. All run: `bd migrate --hash-ids`
4. All push changes
5. New work can continue with hash IDs

**Do NOT**:
- Mix sequential and hash IDs in same database
- Sync before all clones migrate


Delete collision resolution code

Remove ~2,100 LOC of ID collision detection and resolution code (no longer needed with hash IDs).

## Files to Delete Entirely
```
internal/storage/sqlite/collision.go              (~800 LOC)
internal/storage/sqlite/collision_test.go         (~300 LOC)
cmd/bd/autoimport_collision_test.go               (~400 LOC)
```

## Code to Remove from Existing Files

### internal/importer/importer.go
Remove:
- `DetectCollisions()` calls
- `ScoreCollisions()` logic
- `RemapCollisions()` calls
- `handleRename()` function
- All collision-related error handling

Keep:
- Basic import logic
- Exact match detection (idempotent import)

### beads_twoclone_test.go
Remove:
- `TestTwoCloneCollision` (bd-71107098)
- `TestThreeCloneCollision` (bd-cbed9619)
- `TestFiveCloneCollision` (bd-a40f374f)
- All N-way collision tests

### cmd/bd/import.go
Remove:
- `--resolve-collisions` flag
- `--dry-run` collision preview
- Collision reporting

## Issues Closed by This Change
- bd-71107098: Add test for symmetric collision
--89: Content-hash collision resolution
- bd-cbed9619: N-way collision resolution epic
- bd-cbed9619.5: Add ScoreCollisions (already done but now unnecessary)
- bd-cbed9619.4: Make DetectCollisions read-only
- bd-cbed9619.3: ResolveNWayCollisions function
- bd-cbed9619.2: Multi-round import convergence
- bd-cbed9619.1: Multi-round convergence for N-way collisions
- bd-e6d71828: Transaction + retry logic for collisions
- bd-70419816: Test case for symmetric collision

## Verification Steps
1. `grep -r "collision" --include="*.go"` → should only find alias conflicts
2. `go test ./...` → all tests pass
3. `go build ./cmd/bd` → clean build
4. Check LOC reduction: `git diff --stat`

## Expected Metrics
- **Files deleted**: 3
- **LOC removed**: ~2,100
- **Test coverage**: Should increase (less untested code)
- **Binary size**: Slightly smaller

## Caution
Do NOT delete:
- Alias conflict resolution (new code in bd-f8b764c9.6)
- Duplicate detection (bd-581b80b3, bd-149) - different from ID collisions
- Merge conflict resolution (bd-7e7ddffa.1, bd-5f483051) - git conflicts, not ID collisions

## Files to Modify
- internal/importer/importer.go (remove collision handling)
- cmd/bd/import.go (remove --resolve-collisions flag)
- beads_twoclone_test.go (remove collision tests)
- Delete: internal/storage/sqlite/collision.go
- Delete: internal/storage/sqlite/collision_test.go
- Delete: cmd/bd/autoimport_collision_test.go

## Testing
- Ensure all remaining tests pass
- Manual test: create issue on two clones, sync → no collisions
- Verify error if somehow hash collision occurs (extremely unlikely)


Implement alias conflict resolution

Handle alias conflicts when multiple clones assign same alias to different issues.

## Scenario
```
Clone A: Creates bd-a1b2c3d4, assigns alias #42
Clone B: Creates bd-e5f6a7b8, assigns alias #42
After sync: Conflict! Which issue gets #42?
```

## Resolution Strategy: Content-Hash Ordering
Deterministic, same result on all clones:
```go
func ResolveAliasConflicts(conflicts []AliasConflict) []AliasRemapping {
    for _, conflict := range conflicts {
        // Sort by hash ID (lexicographic)
        sort.Strings(conflict.IssueIDs)

        // Winner: lowest hash ID (arbitrary but deterministic)
        winner := conflict.IssueIDs[0]

        // Losers: reassign to next available aliases
        for _, loser := range conflict.IssueIDs[1:] {
            newAlias := getNextAlias()
            remappings = append(remappings, AliasRemapping{
                IssueID:  loser,
                OldAlias: conflict.Alias,
                NewAlias: newAlias,
            })
        }
    }
    return remappings
}
```

## Detection During Import
File: internal/importer/importer.go
```go
func handleAliasConflicts(imported []Issue, existing []Issue) error {
    // Build alias map from imported issues
    aliasMap := make(map[int][]string)  // alias → issue IDs

    for _, issue := range imported {
        aliasMap[issue.Alias] = append(aliasMap[issue.Alias], issue.ID)
    }

    // Check against existing aliases
    for alias, importedIDs := range aliasMap {
        existingID := storage.GetIssueIDByAlias(alias)
        if existingID != "" {
            // Conflict! Resolve it
            allIDs := append(importedIDs, existingID)
            conflicts = append(conflicts, AliasConflict{
                Alias:    alias,
                IssueIDs: allIDs,
            })
        }
    }

    // Resolve and apply
    remappings := ResolveAliasConflicts(conflicts)
    applyAliasRemappings(remappings)
}
```

## Alternative Strategies (For Future Consideration)

### Priority-Based
```go
// Higher priority keeps alias
if issueA.Priority < issueB.Priority {
    winner = issueA
}
```

### Timestamp-Based (Last-Write-Wins)
```go
// Newer issue keeps alias
if issueA.UpdatedAt.After(issueB.UpdatedAt) {
    winner = issueA
}
```

### Manual Resolution
```bash
bd resolve-aliases --manual
# Interactive prompt for each conflict
```

## User Notification
```bash
$ bd sync
✓ Synced 5 issues
⚠ Alias conflicts resolved:
  - Issue bd-e5f6a7b8: alias changed from #42 to #100
  - Issue bd-9a8b7c6d: alias changed from #15 to #101
```

## Files to Create/Modify
- internal/storage/sqlite/alias_conflicts.go (new)
- internal/importer/importer.go (detect conflicts)
- cmd/bd/sync.go (show conflict notifications)

## Testing
- Test two clones assign same alias to different issues
- Test conflict resolution is deterministic (same on all clones)
- Test loser gets new alias
- Test winner keeps original alias
- Test multiple conflicts resolved in one import


CLI accepts both hash IDs and aliases

Update all CLI commands to accept both hash IDs (bd-af78e9a2) and aliases (#42, or just 42).

## Parsing Logic
```go
// internal/utils/id_parser.go
func ParseIssueID(input string) (issueID string, err error) {
    // Hash ID: bd-af78e9a2
    if strings.HasPrefix(input, "bd-") {
        return input, nil
    }

    // Alias: #42 or 42
    aliasStr := strings.TrimPrefix(input, "#")
    alias, err := strconv.Atoi(aliasStr)
    if err != nil {
        return "", fmt.Errorf("invalid issue ID: %s", input)
    }

    // Resolve alias to hash ID
    return storage.GetIssueIDByAlias(alias)
}
```

## Commands to Update
All commands that accept issue IDs:

### 1. bd show
```bash
bd show bd-af78e9a2        # Hash ID
bd show #42                # Alias
bd show 42                 # Alias (shorthand)
bd show bd-af78e9a2 #42    # Mixed (multiple IDs)
```

### 2. bd update
```bash
bd update #42 --status in_progress
bd update bd-af78e9a2 --priority 1
```

### 3. bd close
```bash
bd close #42 --reason "Done"
```

### 4. bd dep add/tree
```bash
bd dep add #42 #1 --type blocks
bd dep tree bd-af78e9a2
```

### 5. bd label add/remove
```bash
bd label add #42 critical
```

### 6. bd merge
```bash
bd merge #42 #43 --into #41
```

## Display Format
Default to showing aliases in output:
```bash
$ bd list
#1   Fix authentication bug          P1  open
#2   Add logging to daemon           P2  open
#42  Investigate jujutsu integration P3  open
```

With `--format=hash` flag:
```bash
$ bd list --format=hash
bd-af78e9a2  Fix authentication bug          P1  open
bd-e5f6a7b8  Add logging to daemon           P2  open
bd-1a2b3c4d  Investigate jujutsu integration P3  open
```

## Files to Modify
- internal/utils/id_parser.go (new)
- cmd/bd/show.go
- cmd/bd/update.go
- cmd/bd/close.go
- cmd/bd/reopen.go
- cmd/bd/dep.go
- cmd/bd/label.go
- cmd/bd/merge.go
- cmd/bd/list.go (add --format flag)

## Testing
- Test hash ID parsing
- Test alias parsing (#42, 42)
- Test mixed IDs in single command
- Test error on invalid ID
- Test alias resolution failure


Update JSONL format to use hash IDs

Update JSONL import/export to use hash IDs, store aliases separately.

## Current JSONL Format
```jsonl
{"id":"bd-1c63eb84","title":"Fix bug","status":"open",...}
{"id":"bd-9063acda","title":"Add test","status":"open",...}
```

## New JSONL Format (Option A: Include Alias)
```jsonl
{"id":"bd-af78e9a2","alias":1,"title":"Fix bug","status":"open",...}
{"id":"bd-e5f6a7b8","alias":2,"title":"Add test","status":"open",...}
```

## New JSONL Format (Option B: Hash ID Only)
```jsonl
{"id":"bd-af78e9a2","title":"Fix bug","status":"open",...}
{"id":"bd-e5f6a7b8","title":"Add test","status":"open",...}
```

Store aliases in separate .beads/aliases.jsonl (local only, git-ignored):
```jsonl
{"hash":"bd-af78e9a2","alias":1}
{"hash":"bd-e5f6a7b8","alias":2}
```

**Recommendation**: Option B (hash only in main JSONL)
- Cleaner git diffs (no alias conflicts)
- Aliases are workspace-local preference
- Main JSONL is canonical, portable

## Export Changes
File: cmd/bd/export.go
```go
// Export issues with hash IDs
for _, issue := range issues {
    json := marshalIssue(issue)  // Uses issue.ID (hash)
    // Don't include alias in JSONL
}

// Separately export aliases to .beads/aliases.jsonl
exportAliases(issues)
```

## Import Changes
File: cmd/bd/import.go, internal/importer/importer.go
```go
// Import issues by hash ID
issue := unmarshalIssue(line)
// Assign new alias on import (don't use incoming alias)
issue.Alias = getNextAlias()

// No collision detection needed! Hash IDs are globally unique
```

## Dependency Reference Format
No change needed - already uses issue IDs:
```json
{"depends_on_id":"bd-af78e9a2","type":"blocks"}
```

## Files to Modify
- cmd/bd/export.go (use hash IDs)
- cmd/bd/import.go (import hash IDs, assign aliases)
- internal/importer/importer.go (remove collision detection!)
- .gitignore (add .beads/aliases.jsonl)

## Testing
- Test export produces hash IDs
- Test import assigns new aliases
- Test dependencies preserved with hash IDs
- Test no collision detection triggered


Implement hash ID generation in CreateIssue

Replace sequential ID generation with hash-based IDs in CreateIssue function.

## Current Behavior (internal/storage/sqlite/sqlite.go)
```go
func (s *SQLiteStorage) CreateIssue(ctx context.Context, issue *types.Issue) error {
    // ID comes from auto-increment counter
    // Collisions possible across clones
}
```

## New Behavior
```go
func (s *SQLiteStorage) CreateIssue(ctx context.Context, issue *types.Issue) error {
    // Generate hash ID if not provided
    if issue.ID == "" {
        issue.ID = idgen.GenerateHashID(
            issue.Title,
            issue.Description,
            time.Now(),
            s.workspaceID,
        )
    }

    // Assign next alias
    issue.Alias = s.getNextAlias()

    // Insert with hash ID + alias
    // ...
}
```

## Workspace ID Generation
Add to database initialization:
```go
// Generate stable workspace ID (persisted in .beads/workspace_id)
workspaceID := getOrCreateWorkspaceID()
```

Options for workspace ID:
1. Hostname + random suffix
2. UUID (random)
3. Git remote URL hash (deterministic per repo)

Recommended: Option 3 (git remote hash) for reproducibility

## Hash Collision Detection
```go
// On insert, check for collision (unlikely but possible)
existing, err := s.GetIssue(ctx, issue.ID)
if err == nil {
    // Hash collision! Add random suffix and retry
    issue.ID = issue.ID + "-" + randomSuffix(4)
}
```

## Files to Create/Modify
- internal/types/id_generator.go (new)
- internal/storage/sqlite/sqlite.go (CreateIssue)
- internal/storage/sqlite/workspace.go (new - workspace ID management)
- .beads/workspace_id (new file, git-ignored)

## Testing
- Test hash ID generation is deterministic
- Test collision detection and retry
- Test workspace ID persistence
- Benchmark: hash generation performance (<1μs)


Refactor sqlite.go into focused modules

Split sqlite.go (2,298 lines) into focused modules: migrations.go, ids.go, issues.go, events.go, dirty.go, db.go. This will improve maintainability and reduce cognitive load.

Files to create:
- migrations.go: Migration registry + runner
- ids.go: ID generation/validation
- issues.go: CRUD helpers
- events.go: Event helpers
- dirty.go: dirty_issues helpers
- db.go: New/open, DSN construction
- tx.go: Transaction helper


Code Health & Technical Debt Cleanup

Comprehensive codebase cleanup to remove dead code, refactor monolithic files, deduplicate utilities, and improve maintainability. Based on ultrathink code health analysis conducted 2025-10-27.

Goals:
- Remove ~1,500 LOC of dead/unreachable code
- Split 2 monolithic files (server.go 2,273 LOC, sqlite.go 2,136 LOC) into focused modules
- Deduplicate scattered utility functions (normalizeLabels, BD_DEBUG checks)
- Consolidate test coverage (2,019 LOC of collision tests)
- Improve code navigation and reduce merge conflicts

Impact: Reduces codebase by ~6-8%, improves maintainability, faster CI/CD

Estimated Effort: 11 days across 4 phases

- All unreachable code identified by `deadcode` analyzer is removed
- RPC server split into <500 LOC files with clear responsibilities
- Duplicate utility functions centralized
- Test coverage maintained or improved
- All tests passing
- Documentation updated


Run final validation and cleanup checks

Final validation pass to ensure all cleanup objectives met and no regressions introduced.

Validation checklist:
1. Dead code verification: `go run golang.org/x/tools/cmd/deadcode@latest -test ./...`
2. Test coverage: `go test -cover ./...`
3. Build verification: `go build ./cmd/bd/`
4. Linting: `golangci-lint run`
5. Integration tests
6. Metrics verification
7. Git clean check

Final metrics to report:
- LOC removed: ~____
- Files deleted: ____
- Files created: ____
- Test coverage: ____%
- Build time: ____ (before/after)
- Test run time: ____ (before/after)

Impact: Confirms all cleanup objectives achieved successfully

- Zero unreachable functions per deadcode analyzer
- All tests pass: `go test ./...`
- Test coverage maintained or improved
- Builds cleanly: `go build ./...`
- Linting shows improvements
- Integration tests all pass
- LOC reduction target achieved (~2,500 LOC)
- No unintended behavior changes
- Git commit messages document all changes

Validation completed:
- LOC: 52,372 lines total
- Dead code: 4 functions in import_shared.go (tracked in bd-6fe4622f)
- Build: ✓ Successful
- Test coverage: ~20-82% across packages
- Test failure: TestTwoCloneCollision (timeout issue)
- Linting: errcheck warnings present (defer close, fmt errors)
- Test time: ~20s

Issues found:
1. bd-6fe4622f: Remove unreachable import functions (renameImportedIssuePrefixes, etc)
2. TestTwoCloneCollision: Daemon killall timeout causing test failure
3. Linting: errcheck violations need fixing


Consider central serialization package for JSON handling

Multiple parts of the codebase handle JSON serialization of issues with slightly different approaches. Consider creating a centralized serialization package to ensure consistency.

Current serialization locations:
- `cmd/bd/export.go` - JSONL export (issues to file)
- `cmd/bd/import.go` - JSONL import (file to issues)
- `internal/rpc/protocol.go` - RPC JSON marshaling
- `internal/storage/memory/memory.go` - In-memory marshaling

Potential benefits:
- Single source of truth for JSON format
- Consistent field naming
- Easier to add new fields
- Centralized validation

Note: This is marked **optional** because:
- Current serialization mostly works
- May not provide enough benefit to justify refactor
- Risk of breaking compatibility

Decision point: Evaluate if benefits outweigh refactoring cost

Impact: TBD based on investigation - may defer to future work

- Create serialization package with documented JSON format
- Migrate export/import to use centralized serialization
- All existing JSONL files can be read with new code
- All tests pass: `go test ./...`
- Export/import round-trip works perfectly
- RPC protocol unchanged (or backwards compatible)

deduplication optional phase-3 refactor serialization


Delete skipped tests for "old buggy behavior"

Three test functions are permanently skipped with comments indicating they test behavior that was fixed in GH#120. These tests will never run again and should be deleted.

Test functions to remove:

1. `cmd/bd/import_collision_test.go:228`
   ```go
   t.Skip("Test expects old buggy behavior - needs rewrite for GH#120 fix")
   ```

2. `cmd/bd/import_collision_test.go:505`
   ```go
   t.Skip("Test expects old buggy behavior - needs rewrite for GH#120 fix")
   ```

3. `internal/storage/sqlite/collision_test.go:919`
   ```go
   t.Skip("Test expects old buggy behavior - needs rewrite for GH#120 fix")
   ```

Impact: Removes ~150 LOC of permanently skipped tests

- Delete the 3 test functions entirely (~150 LOC total)
- Update test file comments to reference GH#120 fix if needed
- All remaining tests pass: `go test ./...`
- No reduction in meaningful test coverage (these test fixed bugs)


Update documentation after code health cleanup

Update all documentation to reflect code structure changes after cleanup phases complete.

Documentation to update:
1. **AGENTS.md** - Update file structure references
2. **CONTRIBUTING.md** (if exists) - Update build/test instructions
3. **Code comments** - Update any outdated references
4. **Package documentation** - Update godoc for reorganized packages

New documentation to add:
1. **internal/util/README.md** - Document shared utilities
2. **internal/debug/README.md** - Document debug logging
3. **internal/rpc/README.md** - Document new file organization
4. **internal/storage/sqlite/migrations/README.md** - Migration system docs

Impact: Keeps documentation in sync with code

- All documentation references to deleted files removed
- New package READMEs written
- Code comments updated for reorganized code
- Migration guide for developers (if needed)
- Architecture diagrams updated (if they exist)


Audit and consolidate collision test coverage

The codebase has 2,019 LOC of collision detection tests across 3 files. Run coverage analysis to identify redundant test cases and consolidate.

Test files:
- `cmd/bd/import_collision_test.go` - 974 LOC
- `cmd/bd/autoimport_collision_test.go` - 750 LOC
- `cmd/bd/import_collision_regression_test.go` - 295 LOC

Total: 2,019 LOC of collision tests

Analysis steps:
1. Run coverage analysis
2. Identify redundant tests
3. Document findings

Consolidation strategy:
- Keep regression tests for critical bugs
- Merge overlapping table-driven tests
- Remove redundant edge case tests covered elsewhere
- Ensure all collision scenarios still tested

Expected outcome: Reduce to ~1,200 LOC (save ~800 lines) while maintaining coverage

Impact: Faster test runs, easier maintenance, clearer test intent

- Coverage analysis completed and documented
- Redundant tests identified (~800 LOC estimated)
- Consolidated test suite maintains or improves coverage
- All remaining tests pass: `go test ./cmd/bd/...`
- Test run time unchanged or faster
- Document which tests were removed and why
- Coverage percentage maintained: `go test -cover ./cmd/bd/` shows same %


Centralize BD_DEBUG logging into debug package

The codebase has 43 scattered instances of `if os.Getenv("BD_DEBUG") != ""` debug checks across 6 files. Centralize into a debug logging package.

Current locations:
- `cmd/bd/main.go` - 15 checks
- `cmd/bd/autoflush.go` - 6 checks
- `cmd/bd/nodb.go` - 4 checks
- `internal/rpc/server.go` - 2 checks
- `internal/rpc/client.go` - 5 checks
- `cmd/bd/daemon_autostart.go` - 11 checks

Target structure:
```
internal/debug/
└── debug.go
```

Benefits:
- Centralized debug logging
- Easier to add structured logging later
- Testable (can mock debug output)
- Consistent debug message format

Impact: Removes 43 scattered checks, improves code clarity

- Create `internal/debug/debug.go` with `Enabled`, `Logf`, `Printf`
- Add unit tests in `internal/debug/debug_test.go` (test with/without BD_DEBUG)
- Replace all 43 instances of `os.Getenv("BD_DEBUG")` checks with `debug.Logf()`
- Verify debug output works: run with `BD_DEBUG=1 bd status`
- All tests pass: `go test ./...`
- No behavior change (output identical to before)


Extract normalizeLabels to shared utility package

The `normalizeLabels` function appears in multiple locations with identical implementation. Extract to a shared utility package.

Current locations:
- `internal/rpc/server.go:37` (53 lines) - full implementation
- `cmd/bd/list.go:50-52` - uses the server version (needs to use new shared version)

Function purpose:
- Trims whitespace from labels
- Removes empty strings
- Deduplicates labels
- Preserves order

Target structure:
```
internal/util/
├── strings.go         # String utilities
    └── NormalizeLabels([]string) []string
```

Impact: DRY principle, single source of truth, easier to test

- Create `internal/util/strings.go` with `NormalizeLabels`
- Add comprehensive unit tests in `internal/util/strings_test.go`
- Update `internal/rpc/server.go` to import and use `util.NormalizeLabels`
- Update `cmd/bd/list.go` to import and use `util.NormalizeLabels`
- Remove duplicate implementations
- All tests pass: `go test ./...`
- Verify label normalization works: test `bd list --label` commands


Extract SQLite migrations into separate files

The file `internal/storage/sqlite/sqlite.go` is 2,136 lines and contains 11 sequential migrations alongside core storage logic. Extract migrations into a versioned system.

Current issues:
- 11 migration functions mixed with core logic
- Hard to see migration history
- Sequential migrations slow database open
- No clear migration versioning

Migration functions to extract:
- `migrateDirtyIssuesTable()`
- `migrateIssueCountersTable()`
- `migrateExternalRefColumn()`
- `migrateCompositeIndexes()`
- `migrateClosedAtConstraint()`
- `migrateCompactionColumns()`
- `migrateSnapshotsTable()`
- `migrateCompactionConfig()`
- `migrateCompactedAtCommitColumn()`
- `migrateExportHashesTable()`
- Plus 1 more (11 total)

Target structure:
```
internal/storage/sqlite/
├── sqlite.go          # Core storage (~800 lines)
├── schema.go          # Table definitions (~200 lines)
├── migrations.go      # Migration orchestration (~200 lines)
└── migrations/        # Individual migrations
    ├── 001_initial_schema.go
    ├── 002_dirty_issues.go
    ├── 003_issue_counters.go
    [... through 011_export_hashes.go]
```

Benefits:
- Clear migration history
- Each migration self-contained
- Easier to review migration changes in PRs
- Future migrations easier to add

- All 11 migrations extracted to separate files
- Migration version tracking in database
- Migrations run in order on fresh database
- Existing databases upgrade correctly
- All tests pass: `go test ./internal/storage/sqlite/...`
- Database initialization time unchanged or improved
- Add migration rollback capability (optional, nice-to-have)


Remove unreachable utility functions

Several small utility functions are unreachable:

Files to clean:
1. `internal/storage/sqlite/hash.go` - `computeIssueContentHash` (line 17)
   - Check if entire file can be deleted if only contains this function

2. `internal/config/config.go` - `FileUsed` (line 151)
   - Delete unused config helper

3. `cmd/bd/git_sync_test.go` - `verifyIssueOpen` (line 300)
   - Delete dead test helper

4. `internal/compact/haiku.go` - `HaikuClient.SummarizeTier2` (line 81)
   - Tier 2 summarization not implemented
   - Options: implement feature OR delete method

Impact: Removes 50-100 LOC depending on decisions

- Remove unreachable functions
- If entire files can be deleted (like hash.go), delete them
- For SummarizeTier2: decide to implement or delete, document decision
- All tests pass: `go test ./...`
- Verify no callers exist for each function


Remove unreachable RPC methods

Several RPC server and client methods are unreachable and should be removed:

Server methods (internal/rpc/server.go):
- `Server.GetLastImportTime` (line 2116)
- `Server.SetLastImportTime` (line 2123)
- `Server.findJSONLPath` (line 2255)

Client methods (internal/rpc/client.go):
- `Client.Import` (line 311) - RPC import not used (daemon uses autoimport)

Evidence:
```bash
go run golang.org/x/tools/cmd/deadcode@latest -test ./...
```

Impact: Removes ~80 LOC of unused RPC code

- Remove the 4 unreachable methods (~80 LOC total)
- Verify no callers: `grep -r "GetLastImportTime\|SetLastImportTime\|findJSONLPath" .`
- All tests pass: `go test ./internal/rpc/...`
- Daemon functionality works: test daemon start/stop/operations


Refactor sqlite.go (2298 lines)

Break down internal/storage/sqlite/sqlite.go into smaller, more focused modules. The file is currently 2298 lines and should be split into logical components.


Wrap git operations in GitClient interface

Create internal/daemonrunner/git.go with GitClient interface (HasUpstream, HasChanges, Commit, Push, Pull). Default implementation using os/exec. Use in Syncer and Run loop for testability.


Document bd edit command and verify MCP exclusion

Follow-up from PR #152:
1. Add "bd edit" to AGENTS.md with "Humans only" note
2. Verify MCP server doesn't expose bd edit command
3. Consider adding test for command registration