Add a full ChannelEditScreen so the SPA can edit an existing channel
(the list/builder could only create). Mirrors the Blazor ChannelEditor
field set via hydrate-then-PUT against GET/PUT /api/channels/{id}.
- api/channels.ts: getChannelById + updateChannel (typed from generated
ChannelViewModel / UpdateChannelRequest).
- screens/ChannelEditScreen.tsx: section-rail form (General, Playout,
Streaming, Stream selection, Music video, Branding) following the
SettingsScreen draft/saved dirtiness + floating save bar pattern. Logo
upload reuses uploadArtwork; option data via existing pickers clients.
- App.tsx: /app/edit-channel/{id} route (allowSubPaths, screen parses the
id); repoint the channel-table edit pencil at it.
- Tests: API-client GET/PUT + screen hydrate/edit-save/404 coverage.
Deferred per scope: ExternalLogoUrl (backend contract gap), and the
/channels/numbers bulk renumber (existing Renumber toolbar = parity).
Language codes / stream selector / credits template are free-text inputs
(no enumeration endpoints exist); mirror-source list can't filter to
Generated-only (ChannelResponseModel omits playoutSource).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
