Refactor WebSocket context + centralize platform flag (#363)

* fix: remove unnecessary websocket.js file and replace its usage directly in `WebSocketContext`

* fix: connect() doesn't need to be async

* fix: update WebSocket context import to use useWebSocket hook

* fix: use `useRef` for WebSocketContext

The main issue with using states was, previously the websocket never closed
properly on unmount, so multiple connections could be opened.

This was because the useEffect cleanup function was closing an old websocket
(that was initialized to null) instead of the current one.

We could have fixed this by adding `ws` to the useEffect dependency array, but
this was unnecessary since `ws` doesn't affect rendering so we shouldn't use a state.

* fix: replace `WebSocketContext` default value with null and add type definitions

* fix: add type definition for WebSocket URL and remove redundant protocol declaration

* fix: Prevent WebSocket reconnection attempts after unmount

Right now, when the WebSocketContext component unmounts,
there is still a pending reconnection attempt that tries
to reconnect the WebSocket after 3 seconds.

* refactor: Extract WebSocket URL construction into a separate function

* refactor: Centralize platform mode detection using IS_PLATFORM constant; use `token` from Auth context in WebSocket connection

* refactor: Use IS_PLATFORM constant for platform detection in authenticatedFetch function (backend)

* refactor: move IS_PLATFORM to config file for both frontend and backend

The reason we couldn't place it in shared/modelConstants.js is that the
frontend uses Vite which requires import.meta.env for environment variables,
while the backend uses process.env. Therefore, we created separate config files
for the frontend (src/constants/config.ts) and backend (server/constants/config.js).

* refactor: update import path for IS_PLATFORM constant to use config file

* refactor: replace `messages` with `latestMessage` in WebSocket context and related components

Why?
Because, messages was only being used to access the latest message in the components it's used in.

* refactor: optimize WebSocket connection handling with useCallback and useMemo

* refactor: comment out debug log for render count in AppContent component

* refactor(backend): update environment variable handling and replace VITE_IS_PLATFORM with IS_PLATFORM constant

* refactor: update WebSocket connection effect to depend on token changes for reconnection

---------

server/constants/config.js

@@ -0,0 +1,5 @@
+/**
+ * Environment Flag: Is Platform
+ * Indicates if the app is running in Platform mode (hosted) or OSS mode (self-hosted)
+ */
+export const IS_PLATFORM = process.env.VITE_IS_PLATFORM === 'true';

server/index.js

@@ -1,5 +1,6 @@
 #!/usr/bin/env node
-// Load environment variables from .env file
+// Load environment variables before other imports execute
+import './load-env.js';
 import fs from 'fs';
 import path from 'path';
 import { fileURLToPath } from 'url';
@@ -28,22 +29,6 @@ const c = {
     dim: (text) => `${colors.dim}${text}${colors.reset}`,
 };
 
-try {
-    const envPath = path.join(__dirname, '../.env');
-    const envFile = fs.readFileSync(envPath, 'utf8');
-    envFile.split('\n').forEach(line => {
-        const trimmedLine = line.trim();
-        if (trimmedLine && !trimmedLine.startsWith('#')) {
-            const [key, ...valueParts] = trimmedLine.split('=');
-            if (key && valueParts.length > 0 && !process.env[key]) {
-                process.env[key] = valueParts.join('=').trim();
-            }
-        }
-    });
-} catch (e) {
-    console.log('No .env file found or error reading it:', e.message);
-}
-
 console.log('PORT from env:', process.env.PORT);
 
 import express from 'express';
@@ -76,6 +61,7 @@ import userRoutes from './routes/user.js';
 import codexRoutes from './routes/codex.js';
 import { initializeDatabase } from './database/db.js';
 import { validateApiKey, authenticateToken, authenticateWebSocket } from './middleware/auth.js';
+import { IS_PLATFORM } from './constants/config.js';
 
 // File system watcher for projects folder
 let projectsWatcher = null;
@@ -200,7 +186,7 @@ const wss = new WebSocketServer({
         console.log('WebSocket connection attempt to:', info.req.url);
 
         // Platform mode: always allow connection
-        if (process.env.VITE_IS_PLATFORM === 'true') {
+        if (IS_PLATFORM) {
             const user = authenticateWebSocket(null); // Will return first user
             if (!user) {
                 console.log('[WARN] Platform mode: No user found in database');

server/load-env.js

@@ -0,0 +1,24 @@
+// Load environment variables from .env before other imports execute.
+import fs from 'fs';
+import path from 'path';
+import { fileURLToPath } from 'url';
+import { dirname } from 'path';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+try {
+  const envPath = path.join(__dirname, '../.env');
+  const envFile = fs.readFileSync(envPath, 'utf8');
+  envFile.split('\n').forEach(line => {
+    const trimmedLine = line.trim();
+    if (trimmedLine && !trimmedLine.startsWith('#')) {
+      const [key, ...valueParts] = trimmedLine.split('=');
+      if (key && valueParts.length > 0 && !process.env[key]) {
+        process.env[key] = valueParts.join('=').trim();
+      }
+    }
+  });
+} catch (e) {
+  console.log('No .env file found or error reading it:', e.message);
+}

server/middleware/auth.js

@@ -1,5 +1,6 @@
 import jwt from 'jsonwebtoken';
 import { userDb } from '../database/db.js';
+import { IS_PLATFORM } from '../constants/config.js';
 
 // Get JWT secret from environment or use default (for development)
 const JWT_SECRET = process.env.JWT_SECRET || 'claude-ui-dev-secret-change-in-production';
@@ -21,7 +22,7 @@ const validateApiKey = (req, res, next) => {
 // JWT authentication middleware
 const authenticateToken = async (req, res, next) => {
   // Platform mode:  use single database user
-  if (process.env.VITE_IS_PLATFORM === 'true') {
+  if (IS_PLATFORM) {
     try {
       const user = userDb.getFirstUser();
       if (!user) {
@@ -80,7 +81,7 @@ const generateToken = (user) => {
 // WebSocket authentication function
 const authenticateWebSocket = (token) => {
   // Platform mode: bypass token validation, return first user
-  if (process.env.VITE_IS_PLATFORM === 'true') {
+  if (IS_PLATFORM) {
     try {
       const user = userDb.getFirstUser();
       if (user) {

server/routes/agent.js

@@ -11,6 +11,7 @@ import { spawnCursor } from '../cursor-cli.js';
 import { queryCodex } from '../openai-codex.js';
 import { Octokit } from '@octokit/rest';
 import { CLAUDE_MODELS, CURSOR_MODELS, CODEX_MODELS } from '../../shared/modelConstants.js';
+import { IS_PLATFORM } from '../constants/config.js';
 
 const router = express.Router();
 
@@ -18,7 +19,7 @@ const router = express.Router();
  * Middleware to authenticate agent API requests.
  *
  * Supports two authentication modes:
- * 1. Platform mode (VITE_IS_PLATFORM=true): For managed/hosted deployments where
+ * 1. Platform mode (IS_PLATFORM=true): For managed/hosted deployments where
  *    authentication is handled by an external proxy. Requests are trusted and
  *    the default user context is used.
  *
@@ -28,7 +29,7 @@ const router = express.Router();
 const validateExternalApiKey = (req, res, next) => {
   // Platform mode: Authentication is handled externally (e.g., by a proxy layer).
   // Trust the request and use the default user context.
-  if (process.env.VITE_IS_PLATFORM === 'true') {
+  if (IS_PLATFORM) {
     try {
       const user = userDb.getFirstUser();
       if (!user) {