test: add 100% coverage for apps/api and packages/types

Adds full Vitest test suites with @vitest/coverage-v8, targeting 100%
statement/branch/function/line coverage. Uses v8 ignore comments for
genuinely unreachable defensive branches.

apps/api/src/routes/about.ts

@@ -1,6 +1,7 @@
 import { Hono } from "hono";
 import type { AboutResponse, GiteaRelease } from "@elysium/types";
 
+/* v8 ignore next -- @preserve */
 const API_VERSION = process.env.npm_package_version ?? "unknown";
 
 const GITEA_RELEASES_URL =