fix: critical database connection pool exhaustion issues

- Disabled duplicate email service (emailService.js) that was creating redundant connections
- Increased connection pool size from 10 to 25 for production environment
- Extended session timeout cache from 5 to 30 minutes to reduce DB queries
- Added connection retry logic with exponential backoff for transient failures
- Fixed password validation to use retry wrapper and correct setting key
- Updated public settings and gallery middleware to handle connection failures gracefully

These changes address the "Connection terminated unexpectedly" errors in production by:
1. Reducing unnecessary database connections
2. Increasing available connection pool capacity
3. Implementing automatic retry for transient connection failures
4. Caching frequently accessed data for longer periods

🤖 Generated with [Claude Code](https://claude.ai/code)

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

backend/src/middleware/gallery.js

@@ -1,5 +1,5 @@
 const jwt = require('jsonwebtoken');
-const { db } = require('../database/db');
+const { db, withRetry } = require('../database/db');
 const { formatBoolean } = require('../utils/dbCompat');
 
 // Middleware to verify gallery access
@@ -11,13 +11,15 @@ async function verifyGalleryAccess(req, res, next) {
     }
     
     const decoded = jwt.verify(token, process.env.JWT_SECRET);
-    const event = await db('events')
-      .where({ 
-        id: decoded.eventId, 
-        is_active: formatBoolean(true),
-        is_archived: formatBoolean(false)
-      })
-      .first();
+    const event = await withRetry(async () => {
+      return await db('events')
+        .where({ 
+          id: decoded.eventId, 
+          is_active: formatBoolean(true),
+          is_archived: formatBoolean(false)
+        })
+        .first();
+    });
     
     if (!event) {
       return res.status(404).json({ error: 'Gallery not found or expired' });

backend/src/middleware/sessionTimeout.js

@@ -10,7 +10,7 @@ const DEFAULT_SESSION_TIMEOUT = 60 * 60 * 1000;
 // Cache for session timeout setting
 let cachedTimeout = null;
 let cacheExpiry = 0;
-const CACHE_DURATION = 5 * 60 * 1000; // 5 minutes
+const CACHE_DURATION = 30 * 60 * 1000; // 30 minutes - reduced DB queries
 
 // Clean up expired sessions every 5 minutes
 setInterval(() => {