Migrate from Supabase to direct PostgreSQL connection

- Replace @supabase/supabase-js with native pg library
- Rewrite database.js to use PostgreSQL connection pool
- Update server.js with PostgreSQL connection testing
- Create postgres-schema.sql with complete database schema
- Add apply-schema.js script for easy schema deployment
- Update all documentation (README.md, DEPLOYMENT.md, deploy.sh)
- Remove Supabase-specific files and references
- Update db.config.example.js with PostgreSQL format

apply-schema.js

@@ -0,0 +1,60 @@
+// Quick script to apply postgres-schema.sql to the database
+// Run with: node apply-schema.js
+
+const fs = require('fs');
+const { Pool } = require('pg');
+const dbConfig = require('./db.config.js');
+
+const pool = new Pool({
+    host: dbConfig.HOST,
+    user: dbConfig.USER,
+    password: dbConfig.PASSWORD,
+    database: dbConfig.DB,
+    port: 5432
+});
+
+async function applySchema() {
+    try {
+        console.log('📄 Reading postgres-schema.sql...');
+        const schema = fs.readFileSync('./postgres-schema.sql', 'utf8');
+        
+        console.log('🔗 Connecting to PostgreSQL...');
+        console.log(`   Host: ${dbConfig.HOST}`);
+        console.log(`   Database: ${dbConfig.DB}`);
+        
+        console.log('⚙️  Applying schema...');
+        await pool.query(schema);
+        
+        console.log('✅ Schema applied successfully!');
+        
+        // Verify tables were created
+        console.log('\n🔍 Verifying tables...');
+        const result = await pool.query(`
+            SELECT table_name 
+            FROM information_schema.tables 
+            WHERE table_schema = 'public' 
+            AND table_name IN ('players', 'active_sessions', 'games', 'game_moves')
+            ORDER BY table_name;
+        `);
+        
+        console.log(`✅ Found ${result.rows.length} tables:`);
+        result.rows.forEach(row => {
+            console.log(`   - ${row.table_name}`);
+        });
+        
+        if (result.rows.length === 4) {
+            console.log('\n🎉 Database setup complete! You can now run: npm start');
+        } else {
+            console.log('\n⚠️  Warning: Expected 4 tables but found', result.rows.length);
+        }
+        
+    } catch (error) {
+        console.error('❌ Error applying schema:', error.message);
+        console.error('\nDetails:', error);
+        process.exit(1);
+    } finally {
+        await pool.end();
+    }
+}
+
+applySchema();