feat: unified message architecture with provider adapters and session store

- Add provider adapter layer (server/providers/) with registry pattern
    - Claude, Cursor, Codex, Gemini adapters normalize native formats to NormalizedMessage
    - Shared types.js defines ProviderAdapter interface and message kinds
    - Registry enables polymorphic provider lookup

  - Add unified REST endpoint: GET /api/sessions/:id/messages?provider=...
    - Replaces four provider-specific message endpoints with one
    - Delegates to provider adapters via registry

  - Add frontend session-keyed store (useSessionStore)
    - Per-session Map with serverMessages/realtimeMessages/merged
    - Dedup by ID, stale threshold for re-fetch, background session accumulation
    - No localStorage for messages — backend JSONL is source of truth

  - Add normalizedToChatMessages converter (useChatMessages)
    - Converts NormalizedMessage[] to existing ChatMessage[] UI format

  - Wire unified store into ChatInterface, useChatSessionState, useChatRealtimeHandlers
    - Session switch uses store cache for instant render
    - Background WebSocket messages routed to correct session slot

server/index.js

@@ -44,7 +44,7 @@ import pty from 'node-pty';
 import fetch from 'node-fetch';
 import mime from 'mime-types';
 
-import { getProjects, getSessions, getSessionMessages, renameProject, deleteSession, deleteProject, addProjectManually, extractProjectDirectory, clearProjectDirectoryCache, searchConversations } from './projects.js';
+import { getProjects, getSessions, renameProject, deleteSession, deleteProject, addProjectManually, extractProjectDirectory, clearProjectDirectoryCache, searchConversations } from './projects.js';
 import { queryClaudeSDK, abortClaudeSDKSession, isClaudeSDKSessionActive, getActiveClaudeSDKSessions, resolveToolApproval, getPendingApprovalsForSession, reconnectSessionWriter } from './claude-sdk.js';
 import { spawnCursor, abortCursorSession, isCursorSessionActive, getActiveCursorSessions } from './cursor-cli.js';
 import { queryCodex, abortCodexSession, isCodexSessionActive, getActiveCodexSessions } from './openai-codex.js';
@@ -65,6 +65,8 @@ import userRoutes from './routes/user.js';
 import codexRoutes from './routes/codex.js';
 import geminiRoutes from './routes/gemini.js';
 import pluginsRoutes from './routes/plugins.js';
+import messagesRoutes from './routes/messages.js';
+import { createNormalizedMessage } from './providers/types.js';
 import { startEnabledPluginServers, stopAllPlugins, getPluginPort } from './utils/plugin-process-manager.js';
 import { initializeDatabase, sessionNamesDb, applyCustomSessionNames } from './database/db.js';
 import { configureWebPush } from './services/vapid-keys.js';
@@ -396,6 +398,9 @@ app.use('/api/gemini', authenticateToken, geminiRoutes);
 // Plugins API Routes (protected)
 app.use('/api/plugins', authenticateToken, pluginsRoutes);
 
+// Unified session messages route (protected)
+app.use('/api/sessions', authenticateToken, messagesRoutes);
+
 // Agent API Routes (uses API key authentication)
 app.use('/api/agent', agentRoutes);
 
@@ -509,31 +514,6 @@ app.get('/api/projects/:projectName/sessions', authenticateToken, async (req, re
     }
 });
 
-// Get messages for a specific session
-app.get('/api/projects/:projectName/sessions/:sessionId/messages', authenticateToken, async (req, res) => {
-    try {
-        const { projectName, sessionId } = req.params;
-        const { limit, offset } = req.query;
-
-        // Parse limit and offset if provided
-        const parsedLimit = limit ? parseInt(limit, 10) : null;
-        const parsedOffset = offset ? parseInt(offset, 10) : 0;
-
-        const result = await getSessionMessages(projectName, sessionId, parsedLimit, parsedOffset);
-
-        // Handle both old and new response formats
-        if (Array.isArray(result)) {
-            // Backward compatibility: no pagination parameters were provided
-            res.json({ messages: result });
-        } else {
-            // New format with pagination info
-            res.json(result);
-        }
-    } catch (error) {
-        res.status(500).json({ error: error.message });
-    }
-});
-
 // Rename project endpoint
 app.put('/api/projects/:projectName/rename', authenticateToken, async (req, res) => {
     try {
@@ -958,7 +938,6 @@ app.get('/api/projects/:projectName/files', authenticateToken, async (req, res)
         }
 
         const files = await getFileTree(actualPath, 10, 0, true);
-        const hiddenFiles = files.filter(f => f.name.startsWith('.'));
         res.json(files);
     } catch (error) {
         console.error('[ERROR] File tree error:', error.message);
@@ -1463,6 +1442,10 @@ wss.on('connection', (ws, request) => {
 
 /**
  * WebSocket Writer - Wrapper for WebSocket to match SSEStreamWriter interface
+ *
+ * Provider files use `createNormalizedMessage()` from `providers/types.js` and
+ * adapter `normalizeMessage()` to produce unified NormalizedMessage events.
+ * The writer simply serialises and sends.
  */
 class WebSocketWriter {
     constructor(ws, userId = null) {
@@ -1474,7 +1457,6 @@ class WebSocketWriter {
 
     send(data) {
         if (this.ws.readyState === 1) { // WebSocket.OPEN
-            // Providers send raw objects, we stringify for WebSocket
             this.ws.send(JSON.stringify(data));
         }
     }
@@ -1555,12 +1537,7 @@ function handleChatConnection(ws, request) {
                     success = await abortClaudeSDKSession(data.sessionId);
                 }
 
-                writer.send({
-                    type: 'session-aborted',
-                    sessionId: data.sessionId,
-                    provider,
-                    success
-                });
+                writer.send(createNormalizedMessage({ kind: 'complete', exitCode: success ? 0 : 1, aborted: true, success, sessionId: data.sessionId, provider }));
             } else if (data.type === 'claude-permission-response') {
                 // Relay UI approval decisions back into the SDK control flow.
                 // This does not persist permissions; it only resolves the in-flight request,
@@ -1576,12 +1553,7 @@ function handleChatConnection(ws, request) {
             } else if (data.type === 'cursor-abort') {
                 console.log('[DEBUG] Abort Cursor session:', data.sessionId);
                 const success = abortCursorSession(data.sessionId);
-                writer.send({
-                    type: 'session-aborted',
-                    sessionId: data.sessionId,
-                    provider: 'cursor',
-                    success
-                });
+                writer.send(createNormalizedMessage({ kind: 'complete', exitCode: success ? 0 : 1, aborted: true, success, sessionId: data.sessionId, provider: 'cursor' }));
             } else if (data.type === 'check-session-status') {
                 // Check if a specific session is currently processing
                 const provider = data.provider || 'claude';