Refactor and improve external URL checks

- Move external URL checks to its own module under `tests/`. This
  separates them from integration test, addressing long runs and
  frequent failures that led to ignoring test results.
- Move `check-desktop-runtime-errors` to `tests/checks` to keep all
  test-related checks into one directory.
- Replace `ts-node` with `vite` for running
  `check-desktop-runtime-errors` to maintain a consistent execution
  environment across checks.
- Implement a timeout for each fetch call.
- Be nice to external sources, wait 5 seconds before sending another
  request to an URL under same domain. This solves rate-limiting issues.
- Instead of running test on every push/pull request, run them only
  weekly.
- Do not run tests on each commit/PR but only scheduled (weekly) to
  minimize noise.
- Fix URLs are not captured correctly inside backticks or parenthesis.

package.json

@@ -12,12 +12,12 @@
     "preview": "vite preview",
     "test:unit": "vitest run --dir tests/unit",
     "test:integration": "vitest run --dir tests/integration",
-    "test:e2e": "vue-cli-service test:e2e",
     "test:cy:run": "start-server-and-test \"vite build && vite preview --port 7070\" http://localhost:7070 \"cypress run --config baseUrl=http://localhost:7070\"",
     "test:cy:open": "start-server-and-test \"vite --port 7070 --mode production\" http://localhost:7070 \"cypress open --config baseUrl=http://localhost:7070\"",
     "lint": "npm run lint:md && npm run lint:md:consistency && npm run lint:md:relative-urls && npm run lint:eslint && npm run lint:yaml",
     "icons:build": "node scripts/logo-update.js",
-    "check:desktop": "ts-node --experimentalSpecifierResolution node --esm scripts/check-desktop-runtime-errors/index.ts",
+    "check:desktop": "vitest run --dir tests/checks/desktop-runtime-errors --environment node",
+    "check:external-urls": "vitest run --dir tests/checks/external-urls --environment node",
     "electron:dev": "electron-vite dev",
     "electron:preview": "electron-vite preview",
     "electron:prebuild": "electron-vite build",
@@ -86,7 +86,6 @@
     "start-server-and-test": "^2.0.0",
     "svgexport": "^0.4.2",
     "terser": "^5.19.2",
-    "ts-node": "^10.9.1",
     "tslib": "~2.4.0",
     "typescript": "~4.6.2",
     "vite": "^4.4.9",