fix: comprehensive boolean compatibility for PostgreSQL and SQLite

- Add formatBoolean() usage to all boolean database queries
- Fix 36 boolean comparisons across 18 backend files
- Ensure compatibility between SQLite (0/1) and PostgreSQL (true/false)
- Update all WHERE clauses and UPDATE operations with boolean values

This completes the database compatibility fixes for production deployment.
All boolean operations now work correctly with both database systems.

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

Co-Authored-By: Claude <[email protected]>

backend/src/middleware/auth.js

@@ -1,5 +1,6 @@
 const jwt = require('jsonwebtoken');
 const { db } = require('../database/db');
+const { formatBoolean } = require('../utils/dbCompat');
 
 async function adminAuth(req, res, next) {
   try {
@@ -9,7 +10,7 @@ async function adminAuth(req, res, next) {
     }
     
     const decoded = jwt.verify(token, process.env.JWT_SECRET);
-    const admin = await db('admin_users').where({ id: decoded.id, is_active: true }).first();
+    const admin = await db('admin_users').where({ id: decoded.id, is_active: formatBoolean(true) }).first();
     
     if (!admin) {
       return res.status(401).json({ error: 'Invalid token' });