Test infrastructure: fixtures, mocks, integration tests

Test infrastructure for Gas Town.

## Test Categories

### Unit Tests
- Config parsing
- Mail operations
- Merge queue operations
- Template rendering

### Integration Tests
- Git operations (uses real git in temp dirs)
- Full workflows (spawn → work → merge)
- CLI command tests

## Fixtures

```go
package testutil

// Creates temp town with minimal structure
func NewTestTown(t *testing.T) *TestTown

// Creates temp rig with git repo
func NewTestRig(t *testing.T, town *TestTown, name string) *TestRig

// Creates test polecat
func NewTestPolecat(t *testing.T, rig *TestRig, name string) *TestPolecat
```

## Mocks

```go
// Mock tmux for session tests (avoid actual tmux)
type MockTmux struct {
    Sessions map[string][]string  // captured send-keys
}

func (m *MockTmux) NewSession(name, dir string) error
func (m *MockTmux) SendKeys(session, keys string) error
func (m *MockTmux) CapturePane(session string, lines int) (string, error)
```

## Test Helpers

```go
// Run test in temp directory
func InTempDir(t *testing.T, fn func(dir string))

// Initialize git repo for testing
func InitGitRepo(t *testing.T, dir string)

// Assert file exists with content
func AssertFileContains(t *testing.T, path, substr string)

// Assert JSON file has field
func AssertJSONField(t *testing.T, path, field string, expected any)
```

## CI Integration

- go test ./... runs all tests
- Integration tests skip with -short flag
- Coverage report generation

## Test Data

Embedded test fixtures:
```go
//go:embed testdata/*
var testdataFS embed.FS
```


Policy beads: config in data plane

Use sentinel/policy beads for configuration instead of external config. Examples: daemon notifications on/off, heartbeat intervals. Config lives in the bead graph, can be toggled by closing/opening policy beads.


Immediate daemon notification on lifecycle request

When gt handoff sends a lifecycle request to the daemon (via bd mail send deacon/), the daemon only discovers it on its next heartbeat poll (every 5 min). Workers wait unnecessarily for retirement.

## Current Behavior
1. Worker runs gt handoff
2. Lifecycle mail sent to deacon/ via beads
3. Worker blocks waiting for retirement
4. Daemon heartbeat runs (up to 5 min later)
5. Daemon processes lifecycle request and kills session

## Expected Behavior
Lifecycle requests should be processed immediately, not on poll interval.

## Proposed Solutions

### Option A: SIGUSR1 Signal (simplest)
1. Add SIGUSR1 handler in daemon that calls ProcessLifecycleRequests()
2. gt handoff reads daemon.pid and sends SIGUSR1 after mail send

### Option B: Unix Socket
1. Daemon listens on ~/gt/daemon/lifecycle.sock
2. gt handoff connects and sends 'process' message

### Option C: Watchfile + fsnotify
1. gt handoff touches ~/gt/daemon/lifecycle.trigger
2. Daemon uses fsnotify to detect and process

Recommend Option A for simplicity.

## Affected Files
- internal/daemon/daemon.go - add signal handler
- internal/cmd/handoff.go - send signal after mail


Merge: gt-rana.3

branch: polecat/dementus
target: main
source_issue: gt-rana.3
rig: gastown


Fix role detection for nested rig structures

When gastown/ has its own mayor/ dir, workspace detection finds it as town root instead of ~/ai. This breaks polecat/refinery/witness detection when running from within a rig.


Phase 2.1: gt spawn --molecule bonds in ephemeral

Make gt spawn molecule-aware with ephemeral bonding.

## New Flag

```bash
gt spawn --issue gt-xxx --molecule mol-polecat-work
```

## Behavior

1. Create polecat with fresh worktree (existing)
2. Bond molecule in ephemeral: `bd mol bond mol-polecat-work --ephemeral`
3. Link molecule root to source issue
4. Include molecule context in work assignment mail
5. Start session

## Work Assignment Mail

```
Subject: Work Assignment: Fix lifecycle bug [MOLECULE]

You are working on gt-rixa as part of molecule mol-polecat-work.

Molecule instance: eph-abc123
Current step: read-assignment (1/8)

Follow the molecule workflow. When complete, generate summary and squash.
```


gt handoff: Deadlock bug in runHandoff

Running 'gt handoff' from a polecat causes a deadlock:

Stack trace shows:
- goroutine 1 [select (no cases)] in runHandoff
- File: internal/cmd/handoff.go:125

The command successfully sends the shutdown request but then hangs with 'fatal error: all goroutines are asleep - deadlock!'


Phase 4.1: mol-deacon-patrol uses ephemeral

Deacon patrol cycles run as ephemeral molecules.

## Current Deacon Loop

```
while running:
    check_heartbeat()
    check_mail()
    sleep(interval)
```

## Molecule-Based Loop

```
while running:
    mol = bd mol bond mol-deacon-patrol-cycle --ephemeral
    execute_cycle(mol):
        check_heartbeat()
        check_mail()
        log_status()
    summary = generate_cycle_summary()
    bd squash mol --summary summary
    sleep(interval)
```

## Benefits

- Each cycle is tracked
- Digests show daemon health over time
- Can query: 'show me patrol cycles from last hour'
- Crash mid-cycle → ephemeral shows where we were


Rollback support: gt mq revert for problematic merges

Implement 'gt mq revert <mr-id>' for rolling back merges.

Actions:
1. Find merge commit from closed MR
2. Create revert commit: git revert <merge-commit>
3. Push revert to target branch
4. Create 'reverted' MR tracking the revert
5. Optionally reopen source issue

Options:
- --reason REASON: required explanation
- --reopen-issue: reopen the source work item

Track revert in MR metadata for audit trail.

Reference: docs/merge-queue-design.md#open-questions


gt spawn --create should auto-add polecat if missing

## Problem

`gt spawn gastown --issue gt-xxx --create` fails if no polecats exist.

## Current Behavior

```
Error: auto-select polecat: no available polecats in rig 'gastown'
```

## Expected Behavior

`--create` should:
1. Create a new polecat if none exist
2. Or create the specified polecat if `gt spawn gastown/NewName --create`

## Workaround

Must manually run `gt polecat add gastown Name` first.

## Principle

Agent UX should be forgiving - if I say spawn with --create, make it work.


Work assignment messages should auto-close on completion

When a polecat completes work on an issue, the work assignment message (msg-type:task) stays open. Found 7 stale work assignments in gastown after swarm completed.

Proposal: When bd close is called on an issue, auto-close any work assignment messages that reference that issue in their body.

Alternative: Work assignment messages could use a different lifecycle - perhaps they should be acked (closed) when the polecat starts working, not when they finish.


Polecats should not bd sync on startup

Polecats all share the same beads database at the rig level. The refinery and mayor/witness manage syncing beads.

## Current Behavior
Polecat startup runs bd sync, causing:
- Contention when multiple polecats spawn simultaneously
- Unnecessary sync operations
- Potential race conditions

## Desired Behavior
- Polecats should NOT run bd sync on startup
- They read from the shared beads database
- Only refinery/witness/mayor sync beads

## Implementation
Remove bd sync from polecat spawn/startup sequence.


Merge: gt-3x1

branch: polecat/Slit
target: main
source_issue: gt-3x1
rig: gastown


Session pre-shutdown checks

Session stop should verify clean state before killing, like PGT.

## Pre-Shutdown Checks

### 1. Git Working Tree Clean
```go
func checkGitClean(clonePath string) error {
    // git status --porcelain
    // Fail if any output
}
```

### 2. All Commits Pushed
```go
func checkCommitsPushed(clonePath string) error {
    // git log origin/HEAD..HEAD
    // Fail if any unpushed commits
}
```

### 3. Assigned Issues Handled
```go
func checkIssuesHandled(polecat *Polecat) error {
    // If polecat.Issue != "", check if closed or reassigned
}
```

### 4. Beads Synced
```go
func checkBeadsSynced(clonePath string) error {
    // bd sync --status in clone directory
}
```

## Behavior on Failure
1. First attempt: Nudge worker to fix
2. Retry up to 3 times with delay
3. After retries: Escalate to Witness/Mayor

## Integration
Modify internal/session/manager.go Stop():
```go
func (m *Manager) Stop(polecat string, force bool) error {
    if !force {
        if err := m.runPreShutdownChecks(polecat); err != nil {
            return fmt.Errorf("pre-shutdown checks failed: %w", err)
        }
    }
    // existing stop logic
}
```

## Flags
- --force: Skip checks
- --grace-period N: Time to wait for fixes

## Dependencies
- Ties into gt-69l (hook system) - can be hook-based
- Ties into gt-f8v (Witness pre-kill verification)

## Acceptance Criteria
- [ ] Stop fails if uncommitted changes (without --force)
- [ ] Stop fails if unpushed commits
- [ ] Clear error messages with fix instructions
- [ ] --force bypasses all checks


Workspace detection: Find() walking up directory tree

Find workspace root by walking up directory tree looking for Gas Town markers.

## Detection Logic

Walk up from current directory, looking for:
1. `config/town.json` - Primary marker (visible config dir per gt-iib)
2. `mayor/` directory at town level - Secondary marker

Stop at filesystem root if neither found.

## Interface

```go
// Find locates the town root from the given directory
func Find(startDir string) (string, error)

// FindOrError is like Find but returns a user-friendly error
func FindOrError(startDir string) (string, error)
```

## Return Values

- Success: Absolute path to town root
- Not found: Empty string + specific error
- Error: Empty string + wrapped error

## Edge Cases

- Symlinks: Follow them (use filepath.EvalSymlinks)
- Permissions: Return error if can't read directory
- Nested towns: Return nearest ancestor (shouldn't happen in practice
EOF
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