feat: add familiar single-key playback controls

README.md

@@ -22,10 +22,20 @@ The layout follows [IINA's video-first window](https://iina.io/img/screenshot.pn
 
 Opening video fits the window to its display aspect ratio, including non-square pixels, and constrains subsequent window resizing. Fullscreen retains the normal letterboxed renderer; audio-only playback and close release the aspect constraint. Extreme ratios that cannot fit both the screen and usable controls keep a freely resizable letterboxed window.
 
-- **Space:** play/pause. **←/→:** seek five seconds. The timeline slider seeks on release and holds the requested position until the core finishes queued seeks; old playback snapshots cannot pull the thumb back.
-- **↑/↓:** adjust volume by five percent. **M:** mute/unmute, restoring the previous audible level. The volume thumb is opaque light gray, independent of the frosted panel behind it.
-- Both slider tracks span the native thumb-center travel range; the orange volume fill ends at the current thumb center.
-- **Double-click video**, **F**, or **⌃⌘F:** toggle native fullscreen. **Esc:** leave fullscreen.
+| Key | Action |
+|---|---|
+| `K` / `Space` | Toggle playback |
+| `M` | Toggle mute, restoring the previous audible level |
+| `J` / `L` | Seek backward / forward ten seconds |
+| `F` | Toggle fullscreen |
+| `P` | Toggle keep-on-top (windowed mode) |
+| `O` | Open the file picker to switch files |
+| `Q` | Quit through normal application shutdown |
+
+Single-key shortcuts apply only to the playback window and do not intercept text editing, file-picker input, or Command/Control/Option combinations. Held toggle keys do not repeatedly toggle; held `J`/`L` can continue seeking. `,` / `.` frame stepping and `C` captions are unbound until supported.
+
+- Existing shortcuts remain: **⌘O** opens files, **←/→** seeks five seconds, **↑/↓** adjusts volume by five percent, **⌃⌘F** toggles fullscreen, and **Esc** leaves fullscreen. Double-clicking video also toggles fullscreen.
+- The timeline slider seeks on release and holds the requested position until queued seeking finishes. Both slider tracks span the native thumb-center travel range; the orange fill ends at the current volume thumb center. The volume thumb is opaque light gray.
 - **Single-click video:** hide controls. Mouse movement reveals them; they fade after 2.5 seconds, including while paused. Hovering the titlebar/controller, dragging, seeking, an inactive window, errors, or VoiceOver keep them visible.
 - Click the right-hand time label to switch between total and remaining time. The titlebar pin keeps the window on top.