Auto-disable daemon in git worktrees for safety (#567)

* feat: auto-disable daemon in git worktrees for safety

Implement worktree daemon compatibility as proposed in the analysis.
The daemon is now automatically disabled when running in a git worktree
unless sync-branch is configured.

Git worktrees share the same .beads directory, and the daemon commits
to whatever branch its working directory has checked out. This causes
commits to go to the wrong branch when using daemon in worktrees.

- Add shouldDisableDaemonForWorktree() helper that checks:
  1. If current directory is a git worktree (via git rev-parse)
  2. If sync-branch is configured (env var or config.yaml)
- Modify shouldAutoStartDaemon() to call the helper
- Modify daemon connection logic in main.go to skip connection
- Add FallbackWorktreeSafety constant for daemon status reporting
- Update warnWorktreeDaemon() to skip warning when sync-branch configured

- In worktree WITHOUT sync-branch: daemon auto-disabled, direct mode used
- In worktree WITH sync-branch: daemon enabled (commits go to dedicated branch)
- In regular repo: no change (daemon works as before)

- Added comprehensive unit tests for shouldDisableDaemonForWorktree()
- Added integration tests for shouldAutoStartDaemon() in worktree contexts
- Manual E2E testing verified correct behavior

- Updated WORKTREES.md with new automatic safety behavior
- Updated DAEMON.md with Git Worktrees section

* feat: check database config for sync-branch in worktree safety logic

Previously, the worktree daemon safety check only looked at:
- BEADS_SYNC_BRANCH environment variable
- sync-branch in config.yaml

This meant users who configured sync-branch via `bd config set sync-branch`
(which stores in the database) would still have daemon disabled in worktrees.

Now the check also reads sync.branch from the database config table,
making daemon work in worktrees when sync-branch is configured via any method.

Changes:
- Add IsConfiguredWithDB() function that checks env, config.yaml, AND database
- Add findBeadsDB() to locate database (worktree-aware via git-common-dir)
- Add getMainRepoRoot() helper using git rev-parse
- Add getConfigFromDB() for lightweight database reads
- Update shouldDisableDaemonForWorktree() to use IsConfiguredWithDB()
- Update warnWorktreeDaemon() to use IsConfiguredWithDB()
- Add test case for database config path

* refactor: use existing beads.FindDatabasePath() instead of duplicating code

Remove duplicate getMainRepoRoot() and findBeadsDB() functions from
syncbranch.go and use the existing beads.FindDatabasePath() which is
already worktree-aware.

Changes:
- Replace custom findBeadsDB() with beads.FindDatabasePath()
- Remove duplicate getMainRepoRoot() (git.GetMainRepoRoot() exists)
- Remove unused imports (exec, strings, filepath)
- Clean up debug logging in tests

---------

Co-authored-by: Charles P. Cross <cpdata@users.noreply.github.com>

docs/WORKTREES.md

@@ -31,53 +31,51 @@ Main Repository
 - ✅ **Concurrent access** - SQLite locking prevents corruption
 - ✅ **Git integration** - Issues sync via JSONL in main repo
 
-### Worktree Detection & Warnings
+### Worktree Detection & Daemon Safety
 
-bd automatically detects when you're in a git worktree and provides appropriate guidance:
+bd automatically detects when you're in a git worktree and handles daemon mode safely:
 
-```bash
-# In a worktree with daemon active
-$ bd ready
-╔══════════════════════════════════════════════════════════════════════════╗
-║ WARNING: Git worktree detected with daemon mode                         ║
-╠══════════════════════════════════════════════════════════════════════════╣
-║ Git worktrees share the same .beads directory, which can cause the      ║
-║ daemon to commit/push to the wrong branch.                               ║
-║                                                                          ║
-║ Shared database: /path/to/main/.beads                                    ║
-║ Worktree git dir: /path/to/shared/.git                                   ║
-║                                                                          ║
-║ RECOMMENDED SOLUTIONS:                                                   ║
-║   1. Use --no-daemon flag:    bd --no-daemon <command>                   ║
-║   2. Disable daemon mode:     export BEADS_NO_DAEMON=1                   ║
-╚══════════════════════════════════════════════════════════════════════════╝
-```
+**Default behavior (no sync-branch configured):**
+- Daemon is **automatically disabled** in worktrees
+- Uses direct mode for safety (no warning needed)
+- All commands work correctly without configuration
+
+**With sync-branch configured:**
+- Daemon is **enabled** in worktrees
+- Commits go to dedicated sync branch (e.g., `beads-metadata`)
+- Full daemon functionality available across all worktrees
 
 ## Usage Patterns
 
-### Recommended: Direct Mode in Worktrees
+### Recommended: Configure Sync-Branch for Full Daemon Support
 
 ```bash
-# Disable daemon for worktree usage
-export BEADS_NO_DAEMON=1
+# Configure sync-branch once (in main repo or any worktree)
+bd config set sync-branch beads-metadata
 
-# Work normally - all commands work correctly
+# Now daemon works safely in all worktrees
 cd feature-worktree
 bd create "Implement feature X" -t feature -p 1
 bd update bd-a1b2 --status in_progress
-bd ready
-bd sync  # Manual sync when needed
+bd ready  # Daemon auto-syncs to beads-metadata branch
 ```
 
-### Alternative: Daemon in Main Repo Only
+### Alternative: Direct Mode (No Configuration Needed)
 
 ```bash
-# Use daemon only in main repository
-cd main-repo
-bd ready  # Daemon works here
+# Without sync-branch, daemon is auto-disabled in worktrees
+cd feature-worktree
+bd create "Implement feature X" -t feature -p 1
+bd ready  # Uses direct mode automatically
+bd sync   # Manual sync when needed
+```
 
-# Use direct mode in worktrees
-cd ../feature-worktree
+### Legacy: Explicit Daemon Disable
+
+```bash
+# Still works if you prefer explicit control
+export BEADS_NO_DAEMON=1
+# or
 bd --no-daemon ready
 ```
 
@@ -160,9 +158,14 @@ bd create "Fix password validation" -t bug -p 0
 
 **Symptoms:** Changes appear on unexpected branch in git history
 
-**Solution:**
+**Note:** This issue should no longer occur with the new worktree safety feature. Daemon is automatically disabled in worktrees unless sync-branch is configured.
+
+**Solution (if still occurring):**
 ```bash
-# Disable daemon in worktrees
+# Option 1: Configure sync-branch (recommended)
+bd config set sync-branch beads-metadata
+
+# Option 2: Explicitly disable daemon
 export BEADS_NO_DAEMON=1
 # Or use --no-daemon flag for individual commands
 bd --no-daemon sync