fix(sessions): live-refresh session list via SSE

[dimakis]

Summary

• The "all sessions" list in desktop only refreshed on page visibility change — new sessions, renames, and deletions were invisible until navigating away and back
• Added a sessions_changed SSE event broadcast from every session mutation point (create, delete, delete-all, rename, auto-rename)
• Frontend useSessionList hook subscribes to the event and refetches the list

Test plan

• Create a new session → session list updates without manual refresh
• Rename a session → title updates in the list immediately
• Delete a session → disappears from the list immediately
• Auto-rename (send first message) → title updates in the list
• Open session list on two tabs → both update when either mutates

🤖 Generated with Claude Code

[dimakis]

Centaur Review

Found 4 issue(s) (1 warning).

frontend/src/hooks/useSessionList.ts

Clean, minimal implementation that correctly wires SSE broadcasts for session mutations. Main gaps are missing test coverage for the new broadcast calls and a lack of debouncing on the frontend consumer.

• 🔵 unsafe_assumptions (L92): No debounce/coalescing on the sessions_changed handler. If multiple events fire in rapid succession (e.g. auto-rename right after create), each triggers a full /api/sessions fetch. The existing session_activity path coalesces via scheduleBroadcast() (200ms), but sessions_changed fires and is consumed immediately. Consider debouncing the handler or coalescing on the server side. [fixable]
• 🔵 unsafe_assumptions (L92): Self-initiated operations (dismissSession, clearAll, handleRename) optimistically update state and then call the server API, which broadcasts sessions_changed back to the same client. This triggers a redundant full refetch that overwrites the already-correct optimistic state. Not harmful, but wasteful — could skip the SSE-triggered refetch for actions the client initiated itself. [fixable]

server/app.ts

Clean, minimal implementation that correctly wires SSE broadcasts for session mutations. Main gaps are missing test coverage for the new broadcast calls and a lack of debouncing on the frontend consumer.

• 🟡 missing_tests (L492): No tests verify that sseRegistry.broadcast('sessions_changed', {}) is called after session create, delete, delete-all, or rename. The existing route tests in server/__tests__/routes.test.ts (lines 402-431) test these endpoints but don't mock or assert on sseRegistry. Similarly, the new setSessionsChangedCallback wiring in chat.ts (line 1003) and index.ts (line 275) has no test coverage. [fixable]

server/chat.ts

Clean, minimal implementation that correctly wires SSE broadcasts for session mutations. Main gaps are missing test coverage for the new broadcast calls and a lack of debouncing on the frontend consumer.

• 🔵 style (L64): The new _onSessionsChanged declaration (lines 64–67) sits between module-level code and an import statement on line 68 (import { EventStore }). This matches the existing pattern for _onSessionChange above it, but imports-after-code is unusual and would be flagged by import/first linting rules. Consider moving the callback declarations below all imports if the file is ever restructured. [fixable]

[dimakis]

🔵 unsafe_assumptions: No debounce/coalescing on the sessions_changed handler. If multiple events fire in rapid succession (e.g. auto-rename right after create), each triggers a full /api/sessions fetch. The existing session_activity path coalesces via scheduleBroadcast() (200ms), but sessions_changed fires and is consumed immediately. Consider debouncing the handler or coalescing on the server side. [fixable]

[dimakis]

🔵 unsafe_assumptions: Self-initiated operations (dismissSession, clearAll, handleRename) optimistically update state and then call the server API, which broadcasts sessions_changed back to the same client. This triggers a redundant full refetch that overwrites the already-correct optimistic state. Not harmful, but wasteful — could skip the SSE-triggered refetch for actions the client initiated itself. [fixable]

[dimakis]

🟡 missing_tests: No tests verify that sseRegistry.broadcast('sessions_changed', {}) is called after session create, delete, delete-all, or rename. The existing route tests in server/__tests__/routes.test.ts (lines 402-431) test these endpoints but don't mock or assert on sseRegistry. Similarly, the new setSessionsChangedCallback wiring in chat.ts (line 1003) and index.ts (line 275) has no test coverage. [fixable]

[dimakis]

🔵 style: The new _onSessionsChanged declaration (lines 64–67) sits between module-level code and an import statement on line 68 (import { EventStore }). This matches the existing pattern for _onSessionChange above it, but imports-after-code is unusual and would be flagged by import/first linting rules. Consider moving the callback declarations below all imports if the file is ever restructured. [fixable]