feat: add health check endpoint

[Arnish-val]

Closes #193

Summary

• Added a lightweight GET /api/health endpoint.
• Returns HTTP 200 with an ok status and version string.
• Added endpoint coverage with Vitest.

Testing

• Verified GET /api/health locally.
• Ran npm test.

[Copilot]

Pull request overview

Adds a lightweight liveness/readiness endpoint to the Express backend so deployments behind proxies/CI can probe server availability without hitting data-heavy routes.

Changes:

• Added GET /api/health returning { status: "ok", version: <string> }.
• Added a Vitest integration test that starts the app and probes /api/health.

Show a summary per file

File	Description
src/server.ts	Adds the /api/health route to the Express app.
src/__tests__/server.test.ts	Adds an integration test that starts a local server and validates the health response.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 3
• Review effort level: Low

[Copilot]

Review details

Suppressed comments (3)

src/server.ts:65

• The new /api/health handler is the only route here without the existing try/catch + JSON 500 error pattern used by the other endpoints. For consistency (and to avoid any unexpected unhandled errors), wrap the handler body in try/catch and return a JSON error on failure.

  // API: Health check
  app.get("/api/health", (_req, res) => {
    res.status(200).json({

      status: "ok",
      version: appVersion,

    });
  });

src/server.ts:57

• These newly added lines contain stray carriage-return characters (mixed CRLF/LF), which can cause noisy diffs and tooling issues. Please normalize line endings in this block to match the rest of the file (LF).

  // Cache version once when the app is created (avoid per-request I/O)

  let appVersion = process.env.npm_package_version;

  if (!appVersion) {

    try {

      appVersion = (require("../package.json") as { version?: string }).version;

src/tests/server.test.ts:44

• If server.address() is missing/unexpected, the test throws before entering the try/finally and the server is never closed. Move the address validation inside the try block so the server is always closed in finally.

    const address = server.address();

    if (!address || typeof address === "string") {
      throw new Error("Test server did not start correctly");
    }

• Files reviewed: 2/2 changed files
• Comments generated: 0 new
• Review effort level: Lite