feat(api): #288/#197 wrap ChannelViewModel + re-key playout/reset to {id}

GetById/Create/Update return ChannelResponseModel via new GetChannelByIdForApi
read-side query; POST /api/channels/{id:int}/playout/reset (new
GetPlayoutIdByChannelId; by-number kept for HlsSessionWorker broadcast).

Refs #288 #197

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/src/api/playouts.test.ts

@@ -115,25 +115,16 @@ describe('playouts api client', () => {
     expect(init).toMatchObject({ method: 'DELETE' });
   });
 
-  it('resetChannelPlayout POSTs to the channel playout reset route without a mode', async () => {
+  it('resetChannelPlayout POSTs to the id-keyed channel playout reset route without a mode', async () => {
     const fetchMock = vi.spyOn(window, 'fetch').mockResolvedValue(jsonResponse({}));
 
-    await resetChannelPlayout('12.3');
+    await resetChannelPlayout(20);
 
     const [url, init] = fetchMock.mock.calls[0];
-    expect(url).toBe('/api/channels/12.3/playout/reset');
+    expect(url).toBe('/api/channels/20/playout/reset');
     expect(init).toMatchObject({ method: 'POST' });
   });
 
-  it('resetChannelPlayout url-encodes the channel number', async () => {
-    const fetchMock = vi.spyOn(window, 'fetch').mockResolvedValue(jsonResponse({}));
-
-    await resetChannelPlayout('a b');
-
-    const [url] = fetchMock.mock.calls[0];
-    expect(url).toBe('/api/channels/a%20b/playout/reset');
-  });
-
   it('erasePlayoutItems POSTs to the erase-items route', async () => {
     const fetchMock = vi.spyOn(window, 'fetch').mockResolvedValue(noContentResponse());
 

web/src/api/playouts.ts

@@ -123,8 +123,9 @@ export function deletePlayout(playoutId: number): Promise<void> {
 
 // Resets the given channel's playout. The server picks the correct default mode per schedule kind
 // (Classic → Refresh, others → Reset), matching the Blazor "Reset Playout" action — so no mode is sent.
-export function resetChannelPlayout(channelNumber: string): Promise<void> {
-  return request<void>(`/api/channels/${encodeURIComponent(channelNumber)}/playout/reset`, { method: 'POST' });
+// Keyed on the immutable channel id (not the user-mutable number), matching the /api/channels/{id} contract.
+export function resetChannelPlayout(channelId: number): Promise<void> {
+  return request<void>(`/api/channels/${channelId}/playout/reset`, { method: 'POST' });
 }
 
 export function erasePlayoutItems(playoutId: number): Promise<void> {