Add episode queueing picker and configurable mpv video output

Activating an episode now opens a scope picker (episode / season / whole
show) and plays the chosen queue back-to-back in one mpv instance, with
only the first item honoring its resume position. A new mpv `vo` driver
setting (CLI flag, env var, config file, and settings TUI) lets users
opt into terminal-based vos like sixel/kitty/tct, which auto-enable
mpv's terminal input so playback keys still work.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

config.toml.example

@@ -6,3 +6,10 @@ password = "your-password-here"
 # codes in priority order; forwarded to mpv's `alang` / `slang`.
 # audio_lang = "jpn,eng"
 # subtitle_lang = "eng"
+
+# Optional mpv video output driver, forwarded as mpv's `vo` property.
+# Common values: gpu (default), gpu-next, sixel, kitty, drm, tct, x11.
+# Terminal-based vos (tct/sixel/kitty/caca) render inside the terminal; the
+# client automatically enables mpv's terminal input for those so keys like
+# q/space/arrow keys reach mpv.
+# video_output = "sixel"