feat(daemon): add auto_pull config parameter for periodic remote sync

Add --auto-pull flag to control whether the daemon periodically pulls from
remote to check for updates from other clones.

Configuration precedence:
1. --auto-pull CLI flag (highest)
2. BEADS_AUTO_PULL environment variable
3. daemon.auto_pull in database config
4. Default: true when sync.branch is configured

When auto_pull is enabled, the daemon creates a remoteSyncTicker that
periodically calls doAutoImport() to pull remote changes. When disabled,
users must manually run 'git pull' to sync remote changes.

Changes:
- cmd/bd/daemon.go: Add --auto-pull flag and config reading logic
- cmd/bd/daemon_event_loop.go: Gate remoteSyncTicker on autoPull parameter
- cmd/bd/daemon_lifecycle.go: Add auto-pull to status output and spawn args
- internal/rpc/protocol.go: Add AutoPull field to StatusResponse
- internal/rpc/server_core.go: Add autoPull to Server struct and SetConfig
- internal/rpc/server_routing_validation_diagnostics.go: Include in status
- Tests updated to pass autoPull parameter

Closes #TBD

internal/rpc/server_routing_validation_diagnostics.go

@@ -280,6 +280,7 @@ func (s *Server) handleStatus(_ *Request) Response {
 	s.mu.RLock()
 	autoCommit := s.autoCommit
 	autoPush := s.autoPush
+	autoPull := s.autoPull
 	localMode := s.localMode
 	syncInterval := s.syncInterval
 	daemonMode := s.daemonMode
@@ -297,6 +298,7 @@ func (s *Server) handleStatus(_ *Request) Response {
 		ExclusiveLockHolder: lockHolder,
 		AutoCommit:          autoCommit,
 		AutoPush:            autoPush,
+		AutoPull:            autoPull,
 		LocalMode:           localMode,
 		SyncInterval:        syncInterval,
 		DaemonMode:          daemonMode,