fix(components): inject tauri calls into useResponseActions

[saagpatel]

What

Small purity fix for `useResponseActions` — the last Wave 5.7 hook that was calling tauri's `invoke` directly from inside its body. The 12 other extracted hooks take their side-effect dependencies as injected options; this PR brings `useResponseActions` onto the same contract.

Why

Caught by the post-Wave-5 verification audit. The hook mixed pure React state with two direct tauri calls (`audit_response_copy_override` and `export_draft`). That meant:

• The hook couldn't be tested without a `vi.mock("@tauri-apps/api/core")` call at the top of the test file.
• The shell couldn't substitute test doubles for the two commands if it wanted to.
• The pattern diverged from the 12 other hooks, making future hook extractions less obvious.

How

1. New `src/components/Draft/draftTauriCommands.ts` module with two stable function exports, `auditResponseCopyOverride` and `exportDraft`, that wrap the tauri `invoke` calls.
2. `useResponseActions` now accepts both as required options.
3. `DraftTab.tsx` imports the two functions from the new module and passes them through at the hook call site.
4. `useResponseActions.test.ts` drops the `vi.mock("@tauri-apps/api/core")` block and its `invokeMock`; tests now assert directly on the injected `options.auditResponseCopyOverride` / `options.exportDraft` spies.

Testing

• `pnpm tsc --noEmit` — clean.
• `pnpm test` — 241 pass, unchanged count (the same 7 tests on this hook, same behavior coverage, just a cleaner mocking strategy).
• `pnpm ui:gate:static` — exit 0.

Risk / Notes

• Runtime behavior unchanged. `draftTauriCommands.ts` calls the exact same tauri commands with the exact same argument shapes.
• No consumer contract changes. `DraftTabHandle` unchanged (still pinned by `DraftTab.handle.test.tsx`).