docs: note in-app streaming and tile view

README.md

@@ -26,6 +26,12 @@ dialog names exactly what will be deleted before anything happens.
 feed sorted by publish date. Thumbnails are mirrored to local disk so the feed still
 renders with no network.
 
+**Undownloaded videos stream in-app.** YouTube's iframe embed refuses a Tauri window —
+its origin is `tauri://localhost`, not an http(s) origin, which produces "Error 153" — so
+`yt-dlp` resolves YouTube's HLS master playlist instead. Its variants are H.264 + AAC up
+to 1080p, which AVFoundation plays natively in WKWebView with adaptive bitrate. One player
+element serves both local files and streams.
+
 **Downloads shell out to `yt-dlp`,** pinned to H.264 video + AAC audio in an MP4
 container. That caps quality at 1080p — YouTube only serves H.264 that high, and anything
 above it is VP9 or AV1, which the app's own player cannot reliably decode. The tradeoff is
@@ -58,9 +64,10 @@ npm run tauri build -- --bundles app && cp -R src-tauri/target/release/bundle/ma
 1. **Settings** — follow the seven-step Takeout guide, then **Import subscriptions.csv**.
 2. **Refresh** — pulls the latest videos from every channel.
 3. **Download** on any video — progress shows live on the button; click again to cancel.
-4. Click a **downloaded** video to play it in the app. Click an undownloaded one to open
-   it on YouTube.
-5. **Offline** — the app detects a lost connection and collapses the feed to your
+4. Click any video to play it **in the app** — a downloaded one from disk, anything else
+   streamed. Nothing hands off to a browser.
+5. **List or Tiles** — switch layouts in the top bar; the choice is remembered.
+6. **Offline** — the app detects a lost connection and collapses the feed to your
    downloads. The connectivity pill also toggles a forced offline mode for testing.
 
 Videos land in `~/Movies/FlightTube` (changeable in Settings). Appearance follows the
@@ -104,7 +111,7 @@ src-tauri/src/
   net.rs         reachability probe
   commands.rs    Tauri command surface — delegates only
 src/
-  components/    Sidebar, TopBar, VideoRow, DownloadButton, Player, Settings
+  components/    Sidebar, TopBar, VideoRow, VideoTile, DownloadButton, Player, Settings
   components/ui.tsx        the design system's component vocabulary, in one place
   components/TakeoutGuide  the seven-step export walkthrough
   hooks/         useFeed, useDownloads, useConnectivity, useAppearance