refactor(web): migrate playlists.ts to api.* wrapper (#375)

Drop 9 hand-rolled apiFetch calls with redundant Content-Type
headers + manual JSON.stringify. The api.* wrapper in client.ts
already handles both. Identical wire shape; existing tests cover
all endpoints.

Also makes api.del generic so DELETE endpoints with typed returns
(playlist track removal) can use the wrapper instead of raw
apiFetch. Default `T = null` preserves existing callers.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/src/lib/api/client.ts

@@ -58,6 +58,6 @@ export const api = {
     apiFetch(path, { method: 'PUT', body: JSON.stringify(body) }) as Promise<T>,
   patch: <T>(path: string, body: unknown): Promise<T> =>
     apiFetch(path, { method: 'PATCH', body: JSON.stringify(body) }) as Promise<T>,
-  del: (path: string): Promise<null> =>
-    apiFetch(path, { method: 'DELETE' }) as Promise<null>
+  del: <T = null>(path: string): Promise<T> =>
+    apiFetch(path, { method: 'DELETE' }) as Promise<T>
 };

web/src/lib/api/playlists.ts

@@ -1,5 +1,5 @@
 import { createQuery } from '@tanstack/svelte-query';
-import { apiFetch } from './client';
+import { api } from './client';
 import { qk } from './queries';
 import type { Playlist, PlaylistDetail } from './types';
 
@@ -12,13 +12,11 @@ export type ListPlaylistsResponse = {
 
 export async function listPlaylists(kind?: PlaylistKind): Promise<ListPlaylistsResponse> {
   const k = kind ?? 'user';
-  return (await apiFetch(`/api/playlists?kind=${k}`, { method: 'GET' })) as ListPlaylistsResponse;
+  return api.get<ListPlaylistsResponse>(`/api/playlists?kind=${k}`);
 }
 
 export async function getPlaylist(id: string): Promise<PlaylistDetail> {
-  return (await apiFetch(`/api/playlists/${encodeURIComponent(id)}`, {
-    method: 'GET'
-  })) as PlaylistDetail;
+  return api.get<PlaylistDetail>(`/api/playlists/${encodeURIComponent(id)}`);
 }
 
 export type CreatePlaylistInput = {
@@ -28,11 +26,7 @@ export type CreatePlaylistInput = {
 };
 
 export async function createPlaylist(input: CreatePlaylistInput): Promise<Playlist> {
-  return (await apiFetch('/api/playlists', {
-    method: 'POST',
-    headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify(input)
-  })) as Playlist;
+  return api.post<Playlist>('/api/playlists', input);
 }
 
 export type UpdatePlaylistInput = {
@@ -42,38 +36,31 @@ export type UpdatePlaylistInput = {
 };
 
 export async function updatePlaylist(id: string, input: UpdatePlaylistInput): Promise<Playlist> {
-  return (await apiFetch(`/api/playlists/${encodeURIComponent(id)}`, {
-    method: 'PATCH',
-    headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify(input)
-  })) as Playlist;
+  return api.patch<Playlist>(`/api/playlists/${encodeURIComponent(id)}`, input);
 }
 
 export async function deletePlaylist(id: string): Promise<void> {
-  await apiFetch(`/api/playlists/${encodeURIComponent(id)}`, { method: 'DELETE' });
+  await api.del(`/api/playlists/${encodeURIComponent(id)}`);
 }
 
 export async function appendTracks(playlistID: string, trackIDs: string[]): Promise<PlaylistDetail> {
-  return (await apiFetch(`/api/playlists/${encodeURIComponent(playlistID)}/tracks`, {
-    method: 'POST',
-    headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify({ track_ids: trackIDs })
-  })) as PlaylistDetail;
+  return api.post<PlaylistDetail>(
+    `/api/playlists/${encodeURIComponent(playlistID)}/tracks`,
+    { track_ids: trackIDs }
+  );
 }
 
 export async function removePlaylistTrack(playlistID: string, position: number): Promise<PlaylistDetail> {
-  return (await apiFetch(
-    `/api/playlists/${encodeURIComponent(playlistID)}/tracks/${position}`,
-    { method: 'DELETE' }
-  )) as PlaylistDetail;
+  return api.del<PlaylistDetail>(
+    `/api/playlists/${encodeURIComponent(playlistID)}/tracks/${position}`
+  );
 }
 
 export async function reorderPlaylist(playlistID: string, orderedPositions: number[]): Promise<PlaylistDetail> {
-  return (await apiFetch(`/api/playlists/${encodeURIComponent(playlistID)}/tracks`, {
-    method: 'PUT',
-    headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify({ ordered_positions: orderedPositions })
-  })) as PlaylistDetail;
+  return api.put<PlaylistDetail>(
+    `/api/playlists/${encodeURIComponent(playlistID)}/tracks`,
+    { ordered_positions: orderedPositions }
+  );
 }
 
 export function createPlaylistsQuery(kind?: PlaylistKind) {
@@ -103,10 +90,7 @@ export type RefreshDiscoverResponse = {
 // returns the resulting Discover playlist's id + track count.
 // Used by the detail-page Refresh button and the home tile kebab.
 export async function refreshDiscover(): Promise<RefreshDiscoverResponse> {
-  return (await apiFetch('/api/playlists/system/discover/refresh', {
-    method: 'POST',
-    body: JSON.stringify({})
-  })) as RefreshDiscoverResponse;
+  return api.post<RefreshDiscoverResponse>('/api/playlists/system/discover/refresh', {});
 }
 
 // For-You refresh ------------------------------------------------------------
@@ -125,7 +109,5 @@ export type RefreshForYouResponse = {
 // triggers refresh, the frontend then calls getPlaylist(new_id) to
 // get full TrackRef snapshots and enqueues for playback.
 export async function refreshForYou(): Promise<RefreshForYouResponse> {
-  return (await apiFetch('/api/playlists/system/for-you/refresh', {
-    method: 'POST'
-  })) as RefreshForYouResponse;
+  return api.post<RefreshForYouResponse>('/api/playlists/system/for-you/refresh', {});
 }