fix(ci): stabilize macOS and web smoke checks

[hongjr03]

Summary

• delay pull-diagnostic refreshes until semantic compilation completes while preserving workspace cleanup refreshes
• use the full integration-test timeout and serialize macOS Rust tests to prevent cold-start timeout storms
• pin, retry, and cache the VS Code Web build used by the web smoke test
• repair platform-pruned native optional packages from lockfile declarations in docs workflows

Verification

• cargo test --workspace -- --test-threads=1 (541 passed, 3 ignored)
• cargo clippy --workspace --all-targets -- -D warnings
• cargo fmt --all -- --check
• cargo xtask check-config-artifacts
• npm test in editors/vscode (54 passed)
• npm run typecheck in editors/vscode/test-web
• node .github/scripts/install-native-optionals.mjs --dry-run website
• actionlint .github/workflows/ci.yml
• git diff --check

[github-actions]

Docs preview: https://vide.pascal-lab.net/preview/pr-319/