chore: document and harden Console CI

[XnLemon]

Summary

• document local verification and observable success signals
• harden ignored frontend/test artifacts
• add a repository PR template and manual CI entry point
• require immutable GitHub Actions and repository hygiene in CI

Verification

• pnpm typecheck
• pnpm test — 48 passed, 0 failed
• pnpm build — production dist/ created
• YAML parse and git diff --check

Fallback delta: removed 0, retained 0, added 0, net 0
Added fallback evidence: none