fix: mock DB and assert no console.error in index route tests

[mahata]

Summary

• Mock getDb in index.test.tsx via vi.mock("../db/index.js", ...), consistent with how channels.test.ts and messages.test.ts already mock the DB. The mock returns an empty array for the #general channel query, making the auto-join code path a clean no-op.
• Add console.error spy that asserts console.error was never called during each test. This turns previously silent stderr noise into explicit test failures, catching regressions immediately.

Problem

The index route handler auto-joins authenticated users to #general by querying D1 via Drizzle ORM. In tests, testApp.ts sets c.env.DB = {} as D1Database (an empty object), so Drizzle queries fail with this.client.prepare is not a function. The route's try/catch swallowed the error via console.error(...), so tests passed with status 200 despite the DB error appearing in stderr.

Verification

• pnpm test:run — 64 tests pass, zero stderr output
• pnpm lint — clean
• pnpm build:check — clean

[Copilot]

Pull request overview

Fixes noisy/hidden DB errors in the index route tests by properly mocking the DB layer and turning unexpected console.error output into explicit test failures, aligning the index tests with existing route test patterns.

Changes:

• Mock getDb (and required schema exports) in index.test.tsx to prevent Drizzle/D1 runtime errors in test env.
• Add a console.error spy per test and assert it was never called.

[Copilot]

afterEach asserts before calling mockRestore(). If the assertion fails, mockRestore() will never run, which can leak the console.error spy into subsequent tests and cause cascading failures. Consider always restoring first (e.g., capture consoleErrorSpy.mock.calls, restore in a finally, then assert on the captured calls).

Suggested change

	expect(consoleErrorSpy).not.toHaveBeenCalled();
	consoleErrorSpy.mockRestore();
	const consoleErrorCalls = consoleErrorSpy.mock.calls;
	consoleErrorSpy.mockRestore();
	expect(consoleErrorCalls.length).toBe(0);