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 <noreply@anthropic.com>

backend/src/routes/adminCategories.js

@@ -1,6 +1,7 @@
 const express = require('express');
 const { body, validationResult } = require('express-validator');
 const { db, logActivity } = require('../database/db');
+const { formatBoolean } = require('../utils/dbCompat');
 const { adminAuth } = require('../middleware/auth-enhanced-v2');
 const router = express.Router();
 
@@ -8,7 +9,7 @@ const router = express.Router();
 router.get('/global', adminAuth, async (req, res) => {
   try {
     const categories = await db('photo_categories')
-      .where('is_global', true)
+      .where('is_global', formatBoolean(true))
       .orderBy('name', 'asc');
     
     res.json(categories);
@@ -25,7 +26,7 @@ router.get('/event/:eventId', adminAuth, async (req, res) => {
     
     const categories = await db('photo_categories')
       .where(function() {
-        this.where('is_global', true)
+        this.where('is_global', formatBoolean(true))
           .orWhere('event_id', eventId);
       })
       .orderBy('is_global', 'desc')
@@ -65,7 +66,7 @@ router.post('/', adminAuth, [
       .where('slug', categorySlug)
       .where(function() {
         if (is_global) {
-          this.where('is_global', true);
+          this.where('is_global', formatBoolean(true));
         } else {
           this.where('event_id', event_id);
         }