[Feat] Save reusable task prompts

[roomote-roomote]

​Created by Roomote. View the task or mention @roomote-roomote for follow-up asks.

What changed

• Added a saved-prompts menu beside the task launch controls.
• Users can save the current prompt, restore any of their eight most recent saved prompts, and clear the collection.
• Saved prompts are kept in user-scoped browser storage, recover safely from malformed data, and stay isolated when accounts change.

Why this change was made

Reusable agent instructions often end up scattered across scratch files. Keeping a small prompt library at the point of task creation makes recurring workflows immediately available without adding backend setup or a separate management surface.

Impact

Users can reuse reliable task instructions directly from Roomote's Home screen. The change is local to the web launch experience and does not alter task routing or execution. Browser screenshots were unavailable because this run did not provide the delegated proof runtime; focused interaction coverage, web type checking, linting, and the repository pre-push checks passed.

[roomote-community]

1 issue outstanding. See task

• Use the existing UUID helper so saving works on plain-HTTP self-hosted deployments (apps/web/src/app/(authenticated)/home/PromptLibraryMenu.tsx:115).

_{Reviewed 009c169}

[roomote-community]

crypto.randomUUID() is unavailable on non-secure origins, so saving a prompt throws for plain-HTTP LAN/self-hosted deployments. The app already has generateClientUuid in @/lib/client-uuid specifically for this case; use that helper here so the save action works outside HTTPS/localhost.