feat: feed UI, in-app player, offline mode, settings

Adds an end-to-end integration test that runs the real pipeline against
live YouTube Atom feeds, verifying the merged feed is newest-first
across channels.

src/api.ts

@@ -0,0 +1,79 @@
+import { invoke, convertFileSrc } from "@tauri-apps/api/core";
+import { listen, type UnlistenFn } from "@tauri-apps/api/event";
+import { open } from "@tauri-apps/plugin-dialog";
+import type {
+  ChannelWithCount,
+  DownloadProgressEvent,
+  DownloadStateEvent,
+  FeedFilter,
+  FeedItem,
+  Prereqs,
+  RefreshProgress,
+  RefreshSummary,
+} from "./types";
+
+export const checkPrereqs = () => invoke<Prereqs>("check_prereqs");
+
+export const listChannels = () => invoke<ChannelWithCount[]>("list_channels");
+
+export const listFeed = (filter: FeedFilter) =>
+  invoke<FeedItem[]>("list_feed", { filter });
+
+export const refreshFeeds = () => invoke<RefreshSummary>("refresh_feeds");
+
+export const downloadVideo = (videoId: string) =>
+  invoke<void>("download_video", { videoId });
+
+export const cancelDownload = (videoId: string) =>
+  invoke<void>("cancel_download", { videoId });
+
+export const deleteDownload = (videoId: string) =>
+  invoke<void>("delete_download", { videoId });
+
+export const getConnectivity = () => invoke<boolean>("get_connectivity");
+
+export const setLibraryPath = (path: string) =>
+  invoke<string>("set_library_path", { path });
+
+export const openExternal = (url: string) =>
+  invoke<void>("open_external", { url });
+
+/** Opens the native file picker for a Takeout subscriptions.csv. */
+export async function pickAndImportTakeout(): Promise<number | null> {
+  const path = await open({
+    multiple: false,
+    directory: false,
+    filters: [{ name: "Takeout subscriptions", extensions: ["csv"] }],
+  });
+  if (typeof path !== "string") return null;
+  return invoke<number>("import_takeout_csv", { path });
+}
+
+export async function pickLibraryFolder(): Promise<string | null> {
+  const path = await open({ directory: true, multiple: false });
+  if (typeof path !== "string") return null;
+  return setLibraryPath(path);
+}
+
+export const onRefreshProgress = (cb: (p: RefreshProgress) => void) =>
+  listen<RefreshProgress>("refresh:progress", (e) => cb(e.payload));
+
+export const onDownloadProgress = (cb: (p: DownloadProgressEvent) => void) =>
+  listen<DownloadProgressEvent>("download:progress", (e) => cb(e.payload));
+
+export const onDownloadState = (cb: (p: DownloadStateEvent) => void) =>
+  listen<DownloadStateEvent>("download:state", (e) => cb(e.payload));
+
+export type { UnlistenFn };
+
+/** Local file path -> a URL the webview is allowed to load. */
+export const fileUrl = (path: string) => convertFileSrc(path);
+
+/**
+ * Prefers the on-disk thumbnail so the feed still renders with no network,
+ * falling back to the remote URL for videos not yet cached.
+ */
+export const thumbSrc = (item: FeedItem, online: boolean) => {
+  if (item.thumb_path) return convertFileSrc(item.thumb_path);
+  return online ? item.thumb_url : "";
+};