chore: prepare standalone public repo

- Remove Mattermost integration (OAuth, channel bridge, file sync watcher,
  frontend import modal). RefBoard now ships as a self-contained app.
- Replace SSO Login screen with email/password form (+ optional register link
  gated by ALLOW_SELF_REGISTRATION).
- Add SEED_ADMIN_EMAIL / SEED_ADMIN_PASSWORD env-var bootstrap so a fresh
  install ships with an admin account on first boot (idempotent).
- ALLOW_SELF_REGISTRATION flag (default false) gates POST /api/auth/register.
  First user can always register (auto-promoted to admin).
- Drop mattermost_id and mm_file_id columns + board_channel_links table
  from the schema; remove related db helpers and exports.
- Add MIT LICENSE, comprehensive README, .env.example, docker-compose.yml
  (bundles MinIO so one command boots a working stack).
- Expand .gitignore for typical Node + Docker dev artefacts.

backend/server.js

@@ -95,22 +95,18 @@ app.get('/api/users/search', (req, res) => {
 
 // ---- API routes ----
 const authRoutes = require('./routes/auth');
-const oauthRoutes = require('./routes/oauth');
 const collectionRoutes = require('./routes/collections');
 const boardRoutes = require('./routes/boards');
 const uploadRoutes = require('./routes/upload');
 const adminRoutes = require('./routes/admin');
-const mmBridgeRoutes = require('./routes/mattermost-bridge');
 const threadRoutes = require('./routes/threads');
 const pdfRoutes = require('./routes/pdf');
 
 app.use('/api/auth', authRoutes);
-app.use('/api/auth', oauthRoutes);
 app.use('/api/collections', collectionRoutes);
 app.use('/api/boards', boardRoutes);
 app.use('/api/upload', uploadRoutes);
 app.use('/api/admin', adminRoutes);
-app.use('/api/boards', mmBridgeRoutes);
 app.use('/api/boards', threadRoutes);
 app.use('/api/boards', pdfRoutes);
 
@@ -161,9 +157,15 @@ app.set('io', io);
 
 // ---- Initialize services and start ----
 async function start() {
-  require('./db');
+  const dbModule = require('./db');
   console.log('[server] Database initialized');
 
+  try {
+    await dbModule.seedAdminFromEnv();
+  } catch (err) {
+    console.error('[server] SEED_ADMIN bootstrap failed:', err.message);
+  }
+
   try {
     const { initBucket } = require('./minio');
     await initBucket();
@@ -173,14 +175,6 @@ async function start() {
     console.error('[server] Image uploads will not work until MinIO is available');
   }
 
-  // Start Mattermost auto-sync watcher (no-op if env vars missing)
-  try {
-    const { startWatcher } = require('./services/mm-watcher');
-    startWatcher(io);
-  } catch (err) {
-    console.error('[server] MM watcher failed to start:', err.message);
-  }
-
   // Start media processing worker
   try {
     const { startMediaWorker } = require('./services/media-worker');
@@ -198,11 +192,6 @@ async function start() {
 function shutdown(signal) {
   console.log(`[server] Received ${signal}, shutting down gracefully...`);
 
-  try {
-    const { stopWatcher } = require('./services/mm-watcher');
-    stopWatcher();
-  } catch {}
-
   try {
     const { stopMediaWorker } = require('./services/media-worker');
     stopMediaWorker();