🤖 fix: code review diff refresh w/ manual feedback

[ammar-agent]

This reintroduces the Code Review diff refresh work from #1296, but with better user-visible feedback when manually refreshing.

Key changes:

• Manual refresh now always provides immediate UI feedback (refresh icon spins on click), even if the refresh resolves too quickly to flip loading state.
• Code review refresh remains event-driven (file-modifying tool-call end events: bash + file_edit_*), with no polling/watchers.
• Origin-based diff refresh is non-interactive (GIT_TERMINAL_PROMPT=0) and deduped per refresh cycle.
• Tooltip shows last refresh time + trigger for debuggability.

Validation:

• make static-check

---

Generated with mux • Model: openai:gpt-5.2 • Thinking: xhigh