fix: resolve all lint errors across source and test files

- Fix unused function parameters (prefix with _)
- Fix unused imports in test files
- Fix import ordering in test files
- Auto-fix formatting issues across 22 files

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/routes/oauth.test.ts

@@ -2,7 +2,6 @@ import { beforeEach, describe, expect, it, mock } from "bun:test";
 import { createHash, randomBytes } from "node:crypto";
 import { Hono } from "hono";
 import { oauthRoutes, wellKnownRoute } from "../../src/server/routes/oauth.ts";
-import { createApiKey } from "../../src/server/services/auth.service.ts";
 import { createTestDb } from "../helpers/db.ts";
 
 // Mock @hono/oidc-auth — must be before importing routes
@@ -35,14 +34,14 @@ function generatePkce() {
 
 describe("OAuth Routes", () => {
 	let app: Hono;
-	let db: Awaited<ReturnType<typeof createTestDb>>["db"];
-	let userId: number;
+	let _db: Awaited<ReturnType<typeof createTestDb>>["db"];
+	let _userId: number;
 
 	beforeEach(async () => {
 		const testApp = await createTestApp();
 		app = testApp.app;
-		db = testApp.db;
-		userId = testApp.userId;
+		_db = testApp.db;
+		_userId = testApp.userId;
 		mockGetAuth.mockReset();
 		// Default: user is authenticated via OIDC
 		mockGetAuth.mockReturnValue({