Fix compilation errors in internal/daemonrunner package

Created missing files:
- logger.go: Logger type, setupLogger method, and env helpers
- signals_unix.go: Unix signal definitions (SIGTERM, SIGINT, SIGHUP)
- signals_windows.go: Windows signal definitions
- sync.go: Sync loop implementation with export/import/validation helpers

Fixed errors:
- Added missing 'version' parameter to acquireDaemonLock call
- Removed duplicate setupLock method from process.go (kept in daemon.go)
- Removed duplicate startRPCServer from daemon.go (kept in rpc.go)
- Fixed LogPath -> LogFile config field reference
- Removed unused 'io' import from process.go

Implementation notes:
- exportToJSONL: Full implementation with dependencies, labels, comments
- importFromJSONL: Placeholder (TODO: extract from cmd/bd/import.go)
- countDBIssues: Uses SQL COUNT(*) optimization with fallback
- validatePostImport: Checks for data loss
- runSyncLoop/runEventLoop: Main daemon event loops with signal handling

All packages now compile successfully with 'go build ./...'

Amp-Thread-ID: https://ampcode.com/threads/T-36a7f730-3420-426f-9e23-f13d5fa089c4
Co-authored-by: Amp <amp@ampcode.com>

cmd/bd/daemon.go

@@ -977,6 +977,7 @@ func setupDaemonLock(pidFile string, dbPath string, log daemonLogger) (io.Closer
 	return lock, nil
 }
 
+// startRPCServer initializes and starts the RPC server (temporary wrapper for old code)
 func startRPCServer(ctx context.Context, socketPath string, store storage.Storage, workspacePath string, dbPath string, log daemonLogger) (*rpc.Server, chan error, error) {
 	// Sync daemon version with CLI version
 	rpc.ServerVersion = Version
@@ -1005,6 +1006,7 @@ func startRPCServer(ctx context.Context, socketPath string, store storage.Storag
 	return server, serverErrChan, nil
 }
 
+// runGlobalDaemon runs the global routing daemon (temporary wrapper for old code)
 func runGlobalDaemon(log daemonLogger) {
 	globalDir, err := getGlobalBeadsDir()
 	if err != nil {