fix: address CodeQL security findings (v0.5.2)

- Rate-limit SPA fallback route (missing rate limiting on fs access)
- Add csrfMiddleware to all state-changing auth routes (logout, create
  user, change password, delete user) — previously bypassed global CSRF
  middleware due to router registration order
- Fix incomplete vCard escaping: escape backslashes before other special
  characters to prevent injection via contact fields
- Restrict CI GITHUB_TOKEN to contents: read (least privilege)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

server/auth.js

@@ -13,7 +13,7 @@ const session = require('express-session');
 const rateLimit = require('express-rate-limit');
 const db = require('./db');
 
-const { generateToken } = require('./middleware/csrf');
+const { generateToken, csrfMiddleware } = require('./middleware/csrf');
 const router = express.Router();
 
 // --------------------------------------------------------
@@ -218,7 +218,7 @@ router.post('/login', loginLimiter, async (req, res) => {
  * POST /api/v1/auth/logout
  * Response: { ok: true }
  */
-router.post('/logout', requireAuth, (req, res) => {
+router.post('/logout', requireAuth, csrfMiddleware, (req, res) => {
   req.session.destroy((err) => {
     if (err) {
       console.error('[Auth] Logout-Fehler:', err);
@@ -274,7 +274,7 @@ router.get('/users', requireAuth, requireAdmin, (req, res) => {
  * Body: { username, display_name, password, avatar_color?, role? }
  * Response: { user: { id, username, display_name, avatar_color, role } }
  */
-router.post('/users', requireAuth, requireAdmin, async (req, res) => {
+router.post('/users', requireAuth, requireAdmin, csrfMiddleware, async (req, res) => {
   try {
     const { username, display_name, password, avatar_color = '#007AFF', role = 'member' } = req.body;
 
@@ -313,7 +313,7 @@ router.post('/users', requireAuth, requireAdmin, async (req, res) => {
  * Body: { current_password: string, new_password: string }
  * Response: { ok: true }
  */
-router.patch('/me/password', requireAuth, async (req, res) => {
+router.patch('/me/password', requireAuth, csrfMiddleware, async (req, res) => {
   try {
     const { current_password, new_password } = req.body;
 
@@ -345,7 +345,7 @@ router.patch('/me/password', requireAuth, async (req, res) => {
  * Admin only. Löscht ein Familienmitglied.
  * Response: { ok: true }
  */
-router.delete('/users/:id', requireAuth, requireAdmin, (req, res) => {
+router.delete('/users/:id', requireAuth, requireAdmin, csrfMiddleware, (req, res) => {
   try {
     const userId = parseInt(req.params.id, 10);
 

server/index.js

@@ -163,10 +163,21 @@ app.get('/health', (req, res) => {
   res.json({ status: 'ok', timestamp: new Date().toISOString() });
 });
 
+// --------------------------------------------------------
+// Rate-Limiter für SPA-Fallback (verhindert Dateisystem-Hammering)
+// --------------------------------------------------------
+const spaLimiter = rateLimit({
+  windowMs: 60_000,
+  max: 200,
+  standardHeaders: true,
+  legacyHeaders: false,
+  message: { error: 'Zu viele Anfragen. Bitte warte kurz.', code: 429 },
+});
+
 // --------------------------------------------------------
 // SPA Fallback: Alle nicht-API-Routen → index.html
 // --------------------------------------------------------
-app.get('*', (req, res) => {
+app.get('*', spaLimiter, (req, res) => {
   if (req.path.startsWith('/api/')) {
     return res.status(404).json({ error: 'Nicht gefunden.', code: 404 });
   }

server/routes/contacts.js

@@ -171,7 +171,7 @@ router.get('/:id/vcard', (req, res) => {
     const contact = db.get().prepare('SELECT * FROM contacts WHERE id = ?').get(id);
     if (!contact) return res.status(404).json({ error: 'Kontakt nicht gefunden', code: 404 });
 
-    const esc = (v) => String(v || '').replace(/\n/g, '\\n').replace(/,/g, '\\,').replace(/;/g, '\\;');
+    const esc = (v) => String(v || '').replace(/\\/g, '\\\\').replace(/\n/g, '\\n').replace(/,/g, '\\,').replace(/;/g, '\\;');
 
     const lines = [
       'BEGIN:VCARD',