feat: add video watch progress tracking with resume functionality

Implements a complete watch progress system that allows users to:
- Save playback position automatically every 5 seconds while watching
- Resume from last position when returning to a video
- Save progress on page leave using sendBeacon for reliability

Also includes:
- Optimized slug generation in projects and workspaces APIs (single query vs loop)
- Added isActive filter to version queries across all video endpoints
- Added pagination support for video and comment queries
- Enhanced database pool management with connection limits and graceful shutdown
- New WatchProgress Prisma model with user-version relations

lib/db.ts

@@ -1,11 +1,52 @@
 import { PrismaClient } from '@prisma/client';
 import { PrismaPg } from '@prisma/adapter-pg';
-import { Pool } from 'pg';
+import { Pool, PoolConfig } from 'pg';
 
 const globalForPrisma = globalThis as unknown as {
   prisma: PrismaClient | undefined;
 };
 
+const globalForPool = globalThis as unknown as {
+  pgPool: Pool | undefined;
+};
+
+function createPool(connectionString: string): Pool {
+  // Prevent multiple pools from being created during development (Next.js hot reload)
+  if (globalForPool.pgPool) {
+    return globalForPool.pgPool;
+  }
+
+  const poolConfig: PoolConfig = {
+    connectionString,
+    max: 20, // Maximum number of connections
+    idleTimeoutMillis: 30000, // Close idle connections after 30 seconds
+    connectionTimeoutMillis: 5000, // Return error after 5 seconds if can't connect
+  };
+
+  const pool = new Pool(poolConfig);
+
+  // Add error handling for pool errors
+  pool.on('error', (err, client) => {
+    console.error('Unexpected database pool error:', err.message);
+    // Don't crash the app on unexpected pool errors
+  });
+
+  pool.on('connect', () => {
+    console.debug('New database connection established');
+  });
+
+  pool.on('acquire', () => {
+    console.debug('Connection acquired from pool');
+  });
+
+  // Store pool globally to prevent multiple instances during development
+  if (process.env.NODE_ENV !== 'production') {
+    globalForPool.pgPool = pool;
+  }
+
+  return pool;
+}
+
 function createPrismaClient() {
   // In development without a database, we'll create a mock-friendly client
   // For production or when DATABASE_URL is set, use the real adapter
@@ -14,13 +55,14 @@ function createPrismaClient() {
   if (!connectionString) {
     console.warn('DATABASE_URL not set - database features will not work');
     // Return a client that will throw clear errors when used
+    const pool = createPool('postgresql://localhost:5432/dummy');
     return new PrismaClient({
       // This will fail on actual DB operations but allows imports to work
-      adapter: new PrismaPg(new Pool({ connectionString: 'postgresql://localhost:5432/dummy' })),
+      adapter: new PrismaPg(pool),
     });
   }
   
-  const pool = new Pool({ connectionString });
+  const pool = createPool(connectionString);
   const adapter = new PrismaPg(pool);
   
   return new PrismaClient({
@@ -35,4 +77,21 @@ if (process.env.NODE_ENV !== 'production') {
   globalForPrisma.prisma = db;
 }
 
+// Graceful shutdown handler
+async function shutdown() {
+  console.log('Shutting down database connections...');
+  
+  if (globalForPool.pgPool) {
+    await globalForPool.pgPool.end();
+    console.log('Database pool closed');
+  }
+  
+  await db.$disconnect();
+  console.log('Prisma client disconnected');
+}
+
+// Register shutdown handlers
+process.on('SIGINT', shutdown);
+process.on('SIGTERM', shutdown);
+
 export default db;