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.

.github/workflows/checks.desktop-runtime-errors.yaml

@@ -6,7 +6,7 @@ on:
   pull_request:
 
 jobs:
-  build-desktop:
+  run-check:
     strategy:
       matrix:
         os: [ macos, ubuntu, windows ]
@@ -60,7 +60,9 @@ jobs:
       -
         name: Test
         shell: bash
-        run: npm run check:desktop -- --screenshot
+        run: |-
+          export SCREENSHOT=true
+          npm run check:desktop
       -
         name: Upload screenshot
         if: always() # Run even if previous step fails