What

Seven response-action callbacks move out of `DraftTab.tsx` into `useResponseActions`:

• `handleCopyResponse` — includes the copy-override audit prompt
• `handleExportResponse`
• `handleCancel`
• `handleResponseChange`
• `handleApplyTemplate`
• `handleSaveAsTemplate`
• `handleTemplateModalSave`

The hook also takes ownership of `showTemplateModal` and `templateModalRating` state.

Shell reduction: 1551 → 1451 LOC (-100 on this PR).

Why

These callbacks cluster around the response text itself — copying it, exporting it, canceling in-flight generation, tracking edits, and saving it as a template. The template modal state belongs with the two template handlers that drive it. Extracting them out of the shell leaves the shell with orchestration-only concerns (handleClear, handleSuggestionApply, conversation-submit, keyboard handlers, tree toggles, view-mode toggles, the imperative handle wire-up, and the JSX tree).

How

1. Create `useResponseActions.ts` with the 7 callbacks + 2 state pieces + `resetResponseActions`.
2. Remove the 2 state declarations (`showTemplateModal`, `templateModalRating`) from the shell.
3. Replace the 3 template/apply callbacks + the 4 copy/export/cancel/change callbacks with a single hook destructure at the appropriate ordering point (after `useDraftGeneration` so `setGenerating` is available).
4. Update `handleClear` to call `resetResponseActions()` instead of touching the two setters individually.
5. Drop now-unused imports: `invoke` from tauri-apps/api/core (moved into the hook), `calculateEditRatio` (only used by handleCopyResponse, now in the hook).
6. Add `useResponseActions.test.ts` (7 tests) covering: direct copy with citations, copy-override prompt path, copy-override cancelled, export success, cancel-with-partial-streaming-text, response-change edit flag, save-as-template modal open.

Testing

• `pnpm tsc --noEmit` — clean.
• `pnpm test` — 234 pass (was 227; +7 new hook tests).
• `pnpm ui:gate:static` — exit 0.

Risk / Notes

• `DraftTabHandle` unchanged (`copyResponse`, `exportResponse`, `cancelGeneration` still point at the hook's exports).
• Copy override audit behavior preserved exactly — `audit_response_copy_override` invocation, prompt text, logEvent payload shape.
• Edit-flag behavior on `handleResponseChange` preserved (sets to `text !== originalResponse`).

Wave 5 status after this PR

• DraftTab: 2573 → 1451 LOC (-1122, ~44% total reduction)
• Tests: 184 → 234 (+50 direct Draft concern tests)
• 12 hooks + 1 panel + 1 handle pin extracted
• ~450 LOC from the 1000-target. One more concern (PR D: useDraftLifecycle for autosave + init + keyboard effects) remains in the roadmap.