fix: update last_import_time when hash matches but mtime is newer

When JSONL mtime changes without content change (e.g., git pull, touch),
the staleness check would repeatedly trigger but auto-import would skip
due to hash match, creating an infinite loop of "Database out of sync"
errors.

Now we update last_import_time even when skipping import due to hash
match, breaking the staleness loop.

Fixes #378

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

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

internal/autoimport/autoimport.go

@@ -98,6 +98,12 @@ func AutoImportIfNewer(ctx context.Context, store storage.Storage, dbPath string
 
 	if currentHash == lastHash {
 		notify.Debugf("auto-import skipped, JSONL unchanged (hash match)")
+		// Update last_import_time to prevent repeated staleness warnings
+		// This handles the case where mtime changed but content didn't (e.g., git pull, touch)
+		importTime := time.Now().Format(time.RFC3339)
+		if err := store.SetMetadata(ctx, "last_import_time", importTime); err != nil {
+			notify.Warnf("failed to update last_import_time: %v", err)
+		}
 		return nil
 	}