fix: multiple production issues with PostgreSQL and connection handling

- Fix trust proxy to use specific values instead of permissive 'true'
- Fix clear old notifications to use database-agnostic date calculation
- Fix database size check to support both PostgreSQL and SQLite
- Add caching and better error handling for session timeout queries
- Add query timeout to prevent hanging connections
- Improve JSON parsing error handling for setting values

These fixes address:
- ERR_ERL_PERMISSIVE_TRUST_PROXY warning
- PostgreSQL datetime function errors
- ENOENT errors looking for SQLite file in PostgreSQL deployment
- Connection terminated errors for session timeout checks

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

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

backend/src/middleware/sessionTimeout.js

@@ -7,6 +7,11 @@ const sessions = new Map();
 // Default session timeout (60 minutes)
 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
+
 // Clean up expired sessions every 5 minutes
 setInterval(() => {
   const now = Date.now();
@@ -18,20 +23,46 @@ setInterval(() => {
 }, 5 * 60 * 1000);
 
 async function getSessionTimeout() {
+  const now = Date.now();
+  
+  // Return cached value if still valid
+  if (cachedTimeout && now < cacheExpiry) {
+    return cachedTimeout;
+  }
+  
   try {
     const setting = await db('app_settings')
       .where('setting_key', 'security_session_timeout_minutes')
-      .first();
+      .first()
+      .timeout(5000); // 5 second timeout
     
     if (setting && setting.setting_value) {
-      const minutes = parseInt(JSON.parse(setting.setting_value));
-      return minutes * 60 * 1000; // Convert to milliseconds
+      let value = setting.setting_value;
+      // Handle both string and object values
+      if (typeof value === 'string') {
+        try {
+          value = JSON.parse(value);
+        } catch (e) {
+          // If it's not JSON, try to parse as number directly
+          value = parseInt(value);
+        }
+      }
+      const minutes = parseInt(value);
+      if (!isNaN(minutes) && minutes > 0) {
+        cachedTimeout = minutes * 60 * 1000; // Convert to milliseconds
+        cacheExpiry = now + CACHE_DURATION;
+        return cachedTimeout;
+      }
     }
   } catch (error) {
-    console.error('Error getting session timeout:', error);
+    // Only log if it's not a connection error (to avoid spam)
+    if (error.code !== 'ECONNRESET' && !error.message?.includes('Connection terminated')) {
+      console.error('Error getting session timeout:', error.message);
+    }
   }
   
-  return DEFAULT_SESSION_TIMEOUT;
+  // Use cached value if available, otherwise default
+  return cachedTimeout || DEFAULT_SESSION_TIMEOUT;
 }
 
 async function sessionTimeoutMiddleware(req, res, next) {