feat: add event bus, WS workspace isolation, and global store migration

- Add internal event bus (server/internal/events/) with synchronous
  pub/sub and panic isolation per listener
- Upgrade WebSocket Hub to workspace-scoped rooms with JWT auth
  and membership verification on connect
- Add 10 new WS event types (comment CRUD, inbox read/archive,
  agent create/delete, workspace/member events)
- Refactor all handlers and TaskService to publish events via Bus
  instead of direct Hub.Broadcast calls
- Add WS broadcast listener that routes events to correct workspace
- Frontend: WSClient sends token + workspace_id on connect with
  auto-reconnect refetch
- Frontend: centralized useRealtimeSync hook dispatches all WS
  events to global Zustand stores
- Migrate issues and inbox pages from local useState to global
  useIssueStore/useInboxStore
- Make store addIssue/addItem idempotent to prevent duplicates
- Remove dead packages/hooks/src/use-realtime.ts
- Add feature tracking files for 4 planned features

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/pkg/protocol/events.go

@@ -7,8 +7,15 @@ const (
 	EventIssueUpdated = "issue:updated"
 	EventIssueDeleted = "issue:deleted"
 
+	// Comment events
+	EventCommentCreated = "comment:created"
+	EventCommentUpdated = "comment:updated"
+	EventCommentDeleted = "comment:deleted"
+
 	// Agent events
-	EventAgentStatus = "agent:status"
+	EventAgentStatus  = "agent:status"
+	EventAgentCreated = "agent:created"
+	EventAgentDeleted = "agent:deleted"
 
 	// Task events (server <-> daemon)
 	EventTaskDispatch  = "task:dispatch"
@@ -17,7 +24,16 @@ const (
 	EventTaskFailed    = "task:failed"
 
 	// Inbox events
-	EventInboxNew = "inbox:new"
+	EventInboxNew      = "inbox:new"
+	EventInboxRead     = "inbox:read"
+	EventInboxArchived = "inbox:archived"
+
+	// Workspace events
+	EventWorkspaceUpdated = "workspace:updated"
+
+	// Member events
+	EventMemberAdded   = "member:added"
+	EventMemberRemoved = "member:removed"
 
 	// Daemon events
 	EventDaemonHeartbeat = "daemon:heartbeat"