Fix bd-ar2 code review issues: metadata tracking and multi-repo support

This commit addresses critical code review findings from bd-dvd and bd-ymj fixes:

## Completed Tasks

### bd-ar2.1: Extract duplicated metadata update code
- Created `updateExportMetadata()` helper function
- Eliminated 22-line duplication between createExportFunc and createSyncFunc
- Single source of truth for metadata updates

### bd-ar2.2: Add multi-repo support to export metadata updates
- Added per-repo metadata key tracking with keySuffix parameter
- Both export and sync functions now update metadata for all repos

### bd-ar2.3: Fix tests to use actual daemon functions
- TestExportUpdatesMetadata now calls updateExportMetadata() directly
- Added TestUpdateExportMetadataMultiRepo() for multi-repo testing
- Fixed export_mtime_test.go tests to call updateExportMetadata()

### bd-ar2.9: Fix variable shadowing in GetNextChildID
- Changed `err` to `resurrectErr` to avoid shadowing
- Improves code clarity and passes linter checks

### bd-ar2.10: Fix hasJSONLChanged to support per-repo keys
- Updated hasJSONLChanged() to accept keySuffix parameter
- Reads metadata with correct per-repo keys
- All callers updated (validatePreExport, daemon import, sync command)

### bd-ar2.11: Use stable repo identifiers instead of paths
- Added getRepoKeyForPath() helper function
- Uses stable identifiers like ".", "../frontend" instead of absolute paths
- Metadata keys now portable across machines and clones
- Prevents orphaned metadata when repos are moved

## Files Changed
- cmd/bd/daemon_sync.go: Helper functions, metadata updates
- cmd/bd/integrity.go: hasJSONLChanged() with keySuffix support
- cmd/bd/sync.go: Updated to use getRepoKeyForPath()
- cmd/bd/*_test.go: Tests updated for new signatures
- internal/storage/sqlite/hash_ids.go: Fixed variable shadowing

## Testing
All export, sync, and integrity tests pass.

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

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

cmd/bd/daemon_sync.go

@@ -8,9 +8,11 @@ import (
 	"os"
 	"path/filepath"
 	"sort"
+	"strings"
 	"time"
 
 	"github.com/steveyegge/beads/internal/beads"
+	"github.com/steveyegge/beads/internal/config"
 	"github.com/steveyegge/beads/internal/storage"
 	"github.com/steveyegge/beads/internal/storage/sqlite"
 	"github.com/steveyegge/beads/internal/types"
@@ -199,6 +201,81 @@ func importToJSONLWithStore(ctx context.Context, store storage.Storage, jsonlPat
 	return err
 }
 
+// getRepoKeyForPath extracts the stable repo identifier from a JSONL path.
+// For single-repo mode, returns empty string (no suffix needed).
+// For multi-repo mode, extracts the repo path (e.g., ".", "../frontend").
+// This creates portable metadata keys that work across different machine paths.
+func getRepoKeyForPath(jsonlPath string) string {
+	multiRepo := config.GetMultiRepoConfig()
+	if multiRepo == nil {
+		return "" // Single-repo mode
+	}
+
+	// Normalize the jsonlPath for comparison
+	// Remove trailing "/.beads/issues.jsonl" to get repo path
+	const suffix = "/.beads/issues.jsonl"
+	if strings.HasSuffix(jsonlPath, suffix) {
+		repoPath := strings.TrimSuffix(jsonlPath, suffix)
+
+		// Try to match against primary repo
+		primaryPath := multiRepo.Primary
+		if primaryPath == "" {
+			primaryPath = "."
+		}
+		if repoPath == primaryPath {
+			return primaryPath
+		}
+
+		// Try to match against additional repos
+		for _, additional := range multiRepo.Additional {
+			if repoPath == additional {
+				return additional
+			}
+		}
+	}
+
+	// Fallback: return empty string for single-repo mode behavior
+	return ""
+}
+
+// updateExportMetadata updates last_import_hash and related metadata after a successful export.
+// This prevents "JSONL content has changed since last import" errors on subsequent exports (bd-ymj fix).
+// In multi-repo mode, keySuffix should be the stable repo identifier (e.g., ".", "../frontend").
+func updateExportMetadata(ctx context.Context, store storage.Storage, jsonlPath string, log daemonLogger, keySuffix string) {
+	currentHash, err := computeJSONLHash(jsonlPath)
+	if err != nil {
+		log.log("Warning: failed to compute JSONL hash for metadata update: %v", err)
+		return
+	}
+
+	// Build metadata keys with optional suffix for per-repo tracking
+	hashKey := "last_import_hash"
+	timeKey := "last_import_time"
+	mtimeKey := "last_import_mtime"
+	if keySuffix != "" {
+		hashKey += ":" + keySuffix
+		timeKey += ":" + keySuffix
+		mtimeKey += ":" + keySuffix
+	}
+
+	if err := store.SetMetadata(ctx, hashKey, currentHash); err != nil {
+		log.log("Warning: failed to update %s: %v", hashKey, err)
+	}
+
+	exportTime := time.Now().Format(time.RFC3339)
+	if err := store.SetMetadata(ctx, timeKey, exportTime); err != nil {
+		log.log("Warning: failed to update %s: %v", timeKey, err)
+	}
+
+	// Store mtime for fast-path optimization
+	if jsonlInfo, statErr := os.Stat(jsonlPath); statErr == nil {
+		mtimeStr := fmt.Sprintf("%d", jsonlInfo.ModTime().Unix())
+		if err := store.SetMetadata(ctx, mtimeKey, mtimeStr); err != nil {
+			log.log("Warning: failed to update %s: %v", mtimeKey, err)
+		}
+	}
+}
+
 // validateDatabaseFingerprint checks that the database belongs to this repository
 func validateDatabaseFingerprint(ctx context.Context, store storage.Storage, log *daemonLogger) error {
 
@@ -306,25 +383,17 @@ func createExportFunc(ctx context.Context, store storage.Storage, autoCommit, au
 		}
 		log.log("Exported to JSONL")
 
-		// Update last_import_hash metadata to prevent "content has changed" errors (bd-ymj fix)
-		// This keeps metadata in sync after export so next export doesn't fail
-		if currentHash, err := computeJSONLHash(jsonlPath); err == nil {
-			if err := store.SetMetadata(exportCtx, "last_import_hash", currentHash); err != nil {
-				log.log("Warning: failed to update last_import_hash: %v", err)
-			}
-			exportTime := time.Now().Format(time.RFC3339)
-			if err := store.SetMetadata(exportCtx, "last_import_time", exportTime); err != nil {
-				log.log("Warning: failed to update last_import_time: %v", err)
-			}
-			// Store mtime for fast-path optimization
-			if jsonlInfo, statErr := os.Stat(jsonlPath); statErr == nil {
-				mtimeStr := fmt.Sprintf("%d", jsonlInfo.ModTime().Unix())
-				if err := store.SetMetadata(exportCtx, "last_import_mtime", mtimeStr); err != nil {
-					log.log("Warning: failed to update last_import_mtime: %v", err)
-				}
+		// Update export metadata (bd-ymj fix, bd-ar2.2 multi-repo support, bd-ar2.11 stable keys)
+		multiRepoPaths := getMultiRepoJSONLPaths()
+		if multiRepoPaths != nil {
+			// Multi-repo mode: update metadata for each JSONL with stable repo key
+			for _, path := range multiRepoPaths {
+				repoKey := getRepoKeyForPath(path)
+				updateExportMetadata(exportCtx, store, path, log, repoKey)
 			}
 		} else {
-			log.log("Warning: failed to compute JSONL hash for metadata update: %v", err)
+			// Single-repo mode: update metadata for main JSONL
+			updateExportMetadata(exportCtx, store, jsonlPath, log, "")
 		}
 
 		// Update database mtime to be >= JSONL mtime (fixes #278, #301, #321)
@@ -408,7 +477,9 @@ func createAutoImportFunc(ctx context.Context, store storage.Storage, log daemon
 
 		// Check JSONL content hash to avoid redundant imports
 		// Use content-based check (not mtime) to avoid git resurrection bug (bd-khnb)
-		if !hasJSONLChanged(importCtx, store, jsonlPath) {
+		// Use getRepoKeyForPath for multi-repo support (bd-ar2.10, bd-ar2.11)
+		repoKey := getRepoKeyForPath(jsonlPath)
+		if !hasJSONLChanged(importCtx, store, jsonlPath, repoKey) {
 			log.log("Skipping import: JSONL content unchanged")
 			return
 		}
@@ -517,25 +588,16 @@ func createSyncFunc(ctx context.Context, store storage.Storage, autoCommit, auto
 		}
 		log.log("Exported to JSONL")
 
-		// Update last_import_hash metadata to prevent "content has changed" errors (bd-ymj fix)
-		// This keeps metadata in sync after export so next export doesn't fail
-		if currentHash, err := computeJSONLHash(jsonlPath); err == nil {
-			if err := store.SetMetadata(syncCtx, "last_import_hash", currentHash); err != nil {
-				log.log("Warning: failed to update last_import_hash: %v", err)
-			}
-			exportTime := time.Now().Format(time.RFC3339)
-			if err := store.SetMetadata(syncCtx, "last_import_time", exportTime); err != nil {
-				log.log("Warning: failed to update last_import_time: %v", err)
-			}
-			// Store mtime for fast-path optimization
-			if jsonlInfo, statErr := os.Stat(jsonlPath); statErr == nil {
-				mtimeStr := fmt.Sprintf("%d", jsonlInfo.ModTime().Unix())
-				if err := store.SetMetadata(syncCtx, "last_import_mtime", mtimeStr); err != nil {
-					log.log("Warning: failed to update last_import_mtime: %v", err)
-				}
+		// Update export metadata (bd-ymj fix, bd-ar2.2 multi-repo support, bd-ar2.11 stable keys)
+		if multiRepoPaths != nil {
+			// Multi-repo mode: update metadata for each JSONL with stable repo key
+			for _, path := range multiRepoPaths {
+				repoKey := getRepoKeyForPath(path)
+				updateExportMetadata(syncCtx, store, path, log, repoKey)
 			}
 		} else {
-			log.log("Warning: failed to compute JSONL hash for metadata update: %v", err)
+			// Single-repo mode: update metadata for main JSONL
+			updateExportMetadata(syncCtx, store, jsonlPath, log, "")
 		}
 
 		// Update database mtime to be >= JSONL mtime (fixes #278, #301, #321)