fix(annotate): show a Done screen, not Feedback Sent, when Done sends nothing

[backnotprop]

Problem

In an annotate session with nothing to send, the header Done posts the nothing-to-send body (nothingToSend: true, #1701). Every host treats that as a no-op: Pi logs "Annotation closed (no feedback).", OpenCode starts no turn, and the Claude Code mod logs it. The completion screen still said Feedback Sent / " will address your feedback on the file".

Cause: handleAnnotateFeedback in packages/editor/App.tsx set the same 'denied' ("feedback sent") state for every annotate submission, and the overlay had no state for nothing-to-send.

Fix

• handleAnnotateFeedback builds the body once and sets a new 'done' completion state when isNothingToSendFeedbackBody(body) is true. That is the same predicate the annotate servers use (packages/shared/annotate-decision.ts), so the screen matches what the host did.
• The overlay shows Done / "Nothing was sent to ." with a neutral check icon. It drops the footer line "Your response has been sent." for this state (CompletionOverlay accepts 'done'; additive, noted in packages/ui/HANDOFF.md).
• Unchanged: Close ("Session Closed"), real feedback ("Feedback Sent"), gated Approve and approve-with-note ("Approved"), and the agent-terminal delivery path.
• WebMCP read_document reports decision: 'done' instead of 'feedback-sent' for this case.

Paths checked: single file, annotate-last (both no-feedback sentences are covered by the sentinel), folder and bundle (same handler and sentinel), raw HTML and live app (same handler), the non-gated discard confirm (posts the zero body, so it also lands on Done), "Send a note…" (it sends a GLOBAL_COMMENT, so it stays "Feedback Sent"), and gated Approve (it posts /api/approve, so it stays "Approved").

Tests

New annotate completion screen block in packages/editor/App.decisionControl.test.tsx, which is already listed in the workflow's DOM_TESTS step. It covers Done at zero, a sent note, discard-all, gated Approve, annotate-last, and raw HTML. Four of the six tests fail without the fix.

• DOM_TESTS=1 bun test --isolate packages/editor: 311 pass
• DOM_TESTS=1 bun test --isolate packages/ui/components: pass
• bun run typecheck: pass
• bun run --cwd apps/review build && bun run build:hook: pass
• bun run --cwd apps/guides-show build:viewer && check:manifest: in sync

[backnotprop]

Follow-up commit 040ca10, from review:

• Close ('exited', "Session Closed") no longer shows the footer line "Your response has been sent." Close sends nothing either. The line only renders in the auto-close closed phase, after an immediate auto-close whose close request went to a host window (Glimpse, or the VS Code panel's parent frame).
• The completion-screen tests now run in that phase, so the footer assertions actually check something. A sent note still shows the line.
• New tests:
  • Close shows "Session Closed" without the line.
  • In a folder session, a comment on a document that is not open (merged from its per-document draft) still shows "Feedback Sent".
• packages/ui/HANDOFF.md notes that ComponentProps<typeof CompletionOverlay>['submitted'] now includes 'done'.
• DOM_TESTS=1 bun test --isolate packages/editor: 313 pass. packages/ui/components + packages/review-editor: 0 fail. Typecheck, review build and hook build pass.