fix: lazy-load database connection to prevent build-time access

Refactor db/index.ts to use lazy initialization via Proxy pattern.
This prevents the database from being accessed at module import time,
which was causing Next.js build failures in CI/CD environments where
no database file exists.

The database connection is now created only when first accessed at
runtime, allowing static site generation to complete successfully.

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

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

apps/web/src/db/index.ts

@@ -7,17 +7,44 @@ import * as schema from './schema'
  *
  * Creates a singleton SQLite connection with Drizzle ORM.
  * Enables foreign key constraints (required for cascading deletes).
+ *
+ * IMPORTANT: The database connection is lazy-loaded to avoid accessing
+ * the database at module import time, which would cause build failures
+ * when the database doesn't exist (e.g., in CI/CD environments).
  */
 
 const databaseUrl = process.env.DATABASE_URL || './data/sqlite.db'
 
-const sqlite = new Database(databaseUrl)
+let _sqlite: Database.Database | null = null
+let _db: ReturnType<typeof drizzle<typeof schema>> | null = null
 
-// Enable foreign keys (SQLite requires explicit enable)
-sqlite.pragma('foreign_keys = ON')
+/**
+ * Get the database connection (lazy-loaded singleton)
+ * Only creates the connection when first accessed at runtime
+ */
+function getDb() {
+  if (!_db) {
+    _sqlite = new Database(databaseUrl)
 
-// Enable WAL mode for better concurrency
-sqlite.pragma('journal_mode = WAL')
+    // Enable foreign keys (SQLite requires explicit enable)
+    _sqlite.pragma('foreign_keys = ON')
+
+    // Enable WAL mode for better concurrency
+    _sqlite.pragma('journal_mode = WAL')
+
+    _db = drizzle(_sqlite, { schema })
+  }
+  return _db
+}
+
+/**
+ * Database client instance
+ * Uses a Proxy to lazy-load the connection on first access
+ */
+export const db = new Proxy({} as ReturnType<typeof drizzle<typeof schema>>, {
+  get(_target, prop) {
+    return getDb()[prop as keyof ReturnType<typeof drizzle<typeof schema>>]
+  }
+})
 
-export const db = drizzle(sqlite, { schema })
 export { schema }