feat: add Drizzle ORM database layer

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

test/db.test.js

@@ -0,0 +1,31 @@
+import { describe, it, expect } from "bun:test";
+import { db, files } from "../src/db/index.js";
+import { files as schemaFiles } from "../src/db/schema.js";
+
+describe("Database Layer", () => {
+  it("should export db instance", () => {
+    expect(db).toBeDefined();
+  });
+
+  it("should export files schema from both index and schema", () => {
+    expect(files).toBeDefined();
+    expect(schemaFiles).toBeDefined();
+    expect(files).toBe(schemaFiles);
+  });
+
+  it("should have correct schema properties", () => {
+    expect(files.id).toBeDefined();
+    expect(files.publicId).toBeDefined();
+    expect(files.telegramFileId).toBeDefined();
+    expect(files.telegramFileUniqueId).toBeDefined();
+    expect(files.storageChatId).toBeDefined();
+    expect(files.storageMessageId).toBeDefined();
+    expect(files.fileName).toBeDefined();
+    expect(files.mimeType).toBeDefined();
+    expect(files.sizeBytes).toBeDefined();
+    expect(files.fileType).toBeDefined();
+    expect(files.uploaderId).toBeDefined();
+    expect(files.createdAt).toBeDefined();
+    expect(files.updatedAt).toBeDefined();
+  });
+});