fix(docs): make page feedback actionable

[vyctorbrzezowski]

Summary

The footer asked Was this useful?, but the buttons did not provide a real path for negative feedback. That made the widget feel like a feedback channel while only changing local UI state.

This keeps the footer lightweight and makes the interaction honest:

• Yes acknowledges the vote and persists that state for the page
• No reveals an inline note field and an Open issue action
• the issue URL targets openclaw/openclaw and includes the docs path, canonical URL, and optional typed detail
• existing Edit source and Raise issue links stay available

Screenshots

Viewport	Yes	No
Desktop
Tablet

Checks

• node --check scripts/docs-site/assets.mjs
• node --check scripts/docs-site/build.mjs
• node --check scripts/docs-site/smoke.mjs
• git diff --check
• npm run docs:build:preview
• node --check dist/docs-site/assets/docs-site.js