refactor: migrate from node-sqlite3-wasm to better-sqlite3

Replace all db.run(sql, [params]) calls with db.prepare(sql).run(...params)
across all source modules and test files. Also remove the node-sqlite3-wasm
import from tests/db.test.ts and update the type annotation accordingly.

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

display/middleware/tests/api/auth.test.ts

@@ -8,10 +8,9 @@ beforeAll(() => {
   const db = initDb(':memory:');
   // Create a test user
   const hash = bcrypt.hashSync('correctpassword', 10);
-  db.run(
-    `INSERT INTO users (username, password_hash) VALUES (?, ?)`,
-    ['testuser', hash]
-  );
+  db.prepare(
+    `INSERT INTO users (username, password_hash) VALUES (?, ?)`
+  ).run('testuser', hash);
 });
 
 afterAll(() => {

display/middleware/tests/api/display-api.test.ts

@@ -9,22 +9,22 @@ beforeAll(() => {
   const db = initDb(':memory:');
 
   // Create a layout
-  db.run(
+  db.prepare(
     `INSERT INTO layouts (id, name, type, width, height)
      VALUES (1, 'Test Layout', 'free', 800, 480)`
-  );
+  ).run();
 
   // Display without token
-  db.run(
+  db.prepare(
     `INSERT INTO displays (id, name, layout_id, refresh_sec)
      VALUES (1, 'Open Display', 1, 60)`
-  );
+  ).run();
 
   // Display with token auth
-  db.run(
+  db.prepare(
     `INSERT INTO displays (id, name, layout_id, api_token, refresh_sec)
      VALUES (2, 'Secure Display', 1, 'secret-token-123', 300)`
-  );
+  ).run();
 });
 
 afterAll(() => {