CI: cleanup and fix broken job references

- Fix code-size -> code-analysis job name (5 jobs had wrong dependency)
- Remove useless install-check job (was no-op)
- Add explicit docs_only guard to release-check
- Remove dead submodule checkout steps (no submodules in repo)
- Rename detect-docs-only -> detect-docs-changes, add docs_changed output
- Reorder check script: format first for faster fail
- Fix billing error test (PR #12946 removed fallback detection but not test)

.github/workflows/install-smoke.yml

@@ -23,7 +23,7 @@ jobs:
 
       - name: Detect docs-only changes
         id: check
-        uses: ./.github/actions/detect-docs-only
+        uses: ./.github/actions/detect-docs-changes
 
   install-smoke:
     needs: [docs-scope]