Implement event-driven daemon improvements for bd-85

- Add mutation events for label/dep/comment operations
- Create separate export-only and import-only functions
- Add dropped events counter with safety net export
- Complete bd-80 mutation channel implementation

Event-driven mode now:
- Emits mutation events for ALL write operations (not just create/update/close)
- Uses createExportFunc() for mutations (export+commit/push only, no pull)
- Uses createAutoImportFunc() for file changes (pull+import only, no export)
- Tracks dropped events and triggers safety export every 60s if any dropped
- Achieves <500ms latency target by avoiding full sync on each trigger

Behind BEADS_DAEMON_MODE=events flag (poll is still default)

internal/rpc/server_core.go

@@ -47,7 +47,8 @@ type Server struct {
 	// Auto-import single-flight guard
 	importInProgress atomic.Bool
 	// Mutation events for event-driven daemon
-	mutationChan chan MutationEvent
+	mutationChan    chan MutationEvent
+	droppedEvents   atomic.Int64 // Counter for dropped mutation events
 }
 
 // MutationEvent represents a database mutation for event-driven sync
@@ -105,7 +106,8 @@ func (s *Server) emitMutation(eventType, issueID string) {
 	}:
 		// Event sent successfully
 	default:
-		// Channel full, event dropped (not critical - sync will happen eventually)
+		// Channel full, increment dropped events counter
+		s.droppedEvents.Add(1)
 	}
 }
 
@@ -113,3 +115,13 @@ func (s *Server) emitMutation(eventType, issueID string) {
 func (s *Server) MutationChan() <-chan MutationEvent {
 	return s.mutationChan
 }
+
+// DroppedEventsCount returns the number of dropped mutation events
+func (s *Server) DroppedEventsCount() int64 {
+	return s.droppedEvents.Load()
+}
+
+// ResetDroppedEventsCount resets the dropped events counter and returns the previous value
+func (s *Server) ResetDroppedEventsCount() int64 {
+	return s.droppedEvents.Swap(0)
+}

internal/rpc/server_labels_deps_comments.go

@@ -34,12 +34,15 @@ func (s *Server) handleDepAdd(req *Request) Response {
 		}
 	}
 
+	// Emit mutation event for event-driven daemon
+	s.emitMutation("update", depArgs.FromID)
+
 	return Response{Success: true}
 }
 
 // Generic handler for simple store operations with standard error handling
 func (s *Server) handleSimpleStoreOp(req *Request, argsPtr interface{}, argDesc string,
-	opFunc func(context.Context, storage.Storage, string) error) Response {
+	opFunc func(context.Context, storage.Storage, string) error, issueID string) Response {
 	if err := json.Unmarshal(req.Args, argsPtr); err != nil {
 		return Response{
 			Success: false,
@@ -57,6 +60,9 @@ func (s *Server) handleSimpleStoreOp(req *Request, argsPtr interface{}, argDesc
 		}
 	}
 
+	// Emit mutation event for event-driven daemon
+	s.emitMutation("update", issueID)
+
 	return Response{Success: true}
 }
 
@@ -64,21 +70,21 @@ func (s *Server) handleDepRemove(req *Request) Response {
 	var depArgs DepRemoveArgs
 	return s.handleSimpleStoreOp(req, &depArgs, "dep remove", func(ctx context.Context, store storage.Storage, actor string) error {
 		return store.RemoveDependency(ctx, depArgs.FromID, depArgs.ToID, actor)
-	})
+	}, depArgs.FromID)
 }
 
 func (s *Server) handleLabelAdd(req *Request) Response {
 	var labelArgs LabelAddArgs
 	return s.handleSimpleStoreOp(req, &labelArgs, "label add", func(ctx context.Context, store storage.Storage, actor string) error {
 		return store.AddLabel(ctx, labelArgs.ID, labelArgs.Label, actor)
-	})
+	}, labelArgs.ID)
 }
 
 func (s *Server) handleLabelRemove(req *Request) Response {
 	var labelArgs LabelRemoveArgs
 	return s.handleSimpleStoreOp(req, &labelArgs, "label remove", func(ctx context.Context, store storage.Storage, actor string) error {
 		return store.RemoveLabel(ctx, labelArgs.ID, labelArgs.Label, actor)
-	})
+	}, labelArgs.ID)
 }
 
 func (s *Server) handleCommentList(req *Request) Response {
@@ -128,6 +134,9 @@ func (s *Server) handleCommentAdd(req *Request) Response {
 		}
 	}
 
+	// Emit mutation event for event-driven daemon
+	s.emitMutation("comment", commentArgs.ID)
+
 	data, _ := json.Marshal(comment)
 	return Response{
 		Success: true,