Switch from Node.js + pnpm to Bun runtime and package manager

Replace @libsql/client with bun:sqlite for zero-dependency SQLite access,
swap drizzle-orm/libsql adapter for drizzle-orm/bun-sqlite, and rewrite
Dockerfile to use oven/bun:1-alpine. The raw Database instance is no longer
exported via Proxy (native C++ methods lose `this` binding through
Reflect.get); instead, a closeDatabase() helper handles graceful shutdown
and the health check uses Drizzle's db.run() directly.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/db/client.ts

@@ -1,23 +1,34 @@
-import { createClient } from "@libsql/client";
-import { drizzle } from "drizzle-orm/libsql";
+import { Database } from "bun:sqlite";
+import path from "node:path";
+import { drizzle } from "drizzle-orm/bun-sqlite";
 import * as schema from "./schema";
 
+// Lazy-init singleton via globalThis. Next.js evaluates module-level code at
+// build time (when no database exists) and re-imports modules on HMR in dev
+// (which would create duplicate connections). Stashing the instances on
+// globalThis and wrapping `db` in a Proxy defers all real work to the first
+// property access at runtime, sidestepping both problems.
+//
+// Only the Drizzle instance (`db`) is exported as a Proxy — the raw bun:sqlite
+// Database is kept internal because its native C++ methods lose their `this`
+// binding when accessed through Reflect.get, so a Proxy around it would break.
+// Use `closeDatabase()` for graceful shutdown instead.
+
 const globalForDb = globalThis as unknown as {
   _db: ReturnType<typeof drizzle> | undefined;
-  _client: ReturnType<typeof createClient> | undefined;
+  _client: Database | undefined;
 };
 
-const DATA_DIR = process.env.DATA_DIR || "./data";
-const DATABASE_URL = process.env.DATABASE_URL || `file:${DATA_DIR}/sqlite.db`;
+const DATABASE_URL =
+  process.env.DATABASE_URL ||
+  path.join(process.env.DATA_DIR || "./data", "sqlite.db");
 
 function getClient() {
   if (!globalForDb._client) {
-    globalForDb._client = createClient({
-      url: DATABASE_URL,
-    });
-    globalForDb._client.execute("PRAGMA journal_mode = WAL");
-    globalForDb._client.execute("PRAGMA foreign_keys = ON");
-    globalForDb._client.execute("PRAGMA busy_timeout = 5000");
+    globalForDb._client = new Database(DATABASE_URL);
+    globalForDb._client.run("PRAGMA journal_mode = WAL");
+    globalForDb._client.run("PRAGMA foreign_keys = ON");
+    globalForDb._client.run("PRAGMA busy_timeout = 5000");
   }
   return globalForDb._client;
 }
@@ -35,8 +46,6 @@ export const db = new Proxy({} as ReturnType<typeof drizzle>, {
   },
 });
 
-export const client = new Proxy({} as ReturnType<typeof createClient>, {
-  get(_, prop) {
-    return Reflect.get(getClient(), prop);
-  },
-});
+export function closeDatabase() {
+  globalForDb._client?.close();
+}

lib/db/migrate.ts

@@ -1,8 +1,8 @@
-import { migrate } from "drizzle-orm/libsql/migrator";
+import { migrate } from "drizzle-orm/bun-sqlite/migrator";
 import { db } from "./client";
 
-export async function runMigrations() {
+export function runMigrations() {
   console.log("[migrate] Running database migrations...");
-  await migrate(db, { migrationsFolder: "./drizzle" });
+  migrate(db, { migrationsFolder: "./drizzle" });
   console.log("[migrate] Database migrations complete");
 }