fix: Code review fixes for auto-migration (bd-jgxi)

Critical fixes from code review:

1. **Moved auto-migration to correct location**
   - Now runs AFTER daemon check but BEFORE opening database
   - Prevents: database opened twice, conflicts with daemon
   - Was: Running too early, before knowing if daemon exists

2. **Fixed context cancellation issue**
   - Check if rootCtx is canceled before using it
   - Fall back to Background() if canceled
   - Fixes: "context canceled" errors in test suite

3. **Updated function signature**
   - Takes dbPath as parameter (no longer searches for it)
   - Simpler, more explicit, easier to test
   - Caller already has dbPath, no need to re-discover

4. **Enhanced test reliability**
   - Save/restore all global state
   - Add debug logging for troubleshooting
   - Verify preconditions before migration

Changes:
- cmd/bd/main.go: Move autoMigrateOnVersionBump call to correct location
- cmd/bd/version_tracking.go: Fix context handling, update signature
- cmd/bd/version_tracking_test.go: Improve test reliability

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

cmd/bd/main.go

@@ -302,10 +302,6 @@ var rootCmd = &cobra.Command{
 		// Best-effort tracking - failures are silent
 		trackBdVersion()
 
-		// Auto-migrate database on version bump (bd-jgxi)
-		// Best-effort migration - failures are silent to avoid disrupting commands
-		autoMigrateOnVersionBump()
-
 		// Initialize daemon status
 		socketPath := getSocketPath()
 		daemonStatus = DaemonStatus{
@@ -479,6 +475,11 @@ var rootCmd = &cobra.Command{
 			debug.Logf("using direct mode (reason: %s)", daemonStatus.FallbackReason)
 		}
 
+		// Auto-migrate database on version bump (bd-jgxi)
+		// Do this AFTER daemon check but BEFORE opening database for main operation
+		// This ensures: 1) no daemon has DB open, 2) we don't open DB twice
+		autoMigrateOnVersionBump(dbPath)
+
 		// Fall back to direct storage access
 		var err error
 		store, err = sqlite.New(rootCtx, dbPath)