Task: Load AI Design video duration options from server

Identity

Update the AI Design video confirmation card to use the active Quote's server-provided generationOptions.durations for both rendering and validation, removing the client-side 2–6 second range coupling.
Add a regression proving an enabled duration outside the former local range is rendered, can be selected, re-quoted, and submitted through the existing confirmation flow.
Do not change the API payload or provider contract; the server Quote remains the authority for available and disabled durations.

Preserve disabled options and the existing “must re-quote after changing a parameter” behavior.
Keep legacy/invalid quotes fail-closed when no enabled server duration is selected; use a server-driven validation message rather than naming a local range.
Keep the local preview adapter unchanged; this change targets the cloud Makelore adapter and the shared Quote confirmation UI.

ImageCanvas now renders enabled video durations directly from the active server Quote's generationOptions.durations.
Confirmation validation now accepts only a non-null duration that matches an enabled server option; the previous client-side 2–6 second range check was removed so future server configuration changes do not require a client release.
The confirmation error is server-driven and no longer names a local range.
Added a regression using server-provided 7 and 15 second options that verifies the options are shown, the initial invalid selection is blocked, 15 survives re-quoting, and the final confirmation receives 15.

Red test: the new regression initially received only ['', '2', '6'], proving the old client-side range filter was still active.
pnpm exec vitest run tests/unit/image-canvas-page.test.tsx tests/unit/works-square-design-workspace.test.ts — 79 passed.
pnpm run typecheck — passed.
pnpm exec eslint src/pages/ImageCanvas/index.tsx tests/unit/image-canvas-page.test.tsx — passed.
pnpm run build:vite — passed for Renderer, Electron Main, and Preload; only existing dynamic-import and chunk-size warnings were reported.
git diff --check — passed; Git reported only the repository's LF-to-CRLF checkout warnings.

The server must continue publishing a valid enabled duration list in each video Quote; an empty or all-disabled list intentionally keeps confirmation unavailable.