Per-tile stream quality (high/low), fps cap, latency flags

Cameras carry multiple stream URLs (streams: high/medium/low); each
tile picks one via Quality (auto/high/low). Small tiles can pull the
low substream to cut Pi decode load. discover --enable-rtsp takes a
comma list (high,low), enables each channel, records all enabled ones.
TUI: q cycles a tile quality (shown in the tile); discover enables
high+low. Player: --framedrop + low-delay demuxer flags; player.max_fps.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

internal/player/player.go

@@ -81,11 +81,16 @@ func (p *Player) args() []string {
 		"--title=" + p.Title(),
 		"--input-ipc-server=" + p.ipcPath,
 		"--hwdec=" + p.cfg.HWDec,
-		// Live-stream hygiene: prefer TCP transport, keep buffers small.
+		// Live-stream hygiene: TCP transport, no caching, and drop frames when
+		// behind so latency self-corrects instead of accumulating a backlog.
 		"--rtsp-transport=tcp",
 		"--profile=low-latency",
 		"--cache=no",
-		"--demuxer-lavf-o=stimeout=5000000",
+		"--framedrop=decoder+vo",
+		"--demuxer-lavf-o=stimeout=5000000,fflags=+nobuffer,flags=+low_delay",
+	}
+	if p.cfg.MaxFPS > 0 {
+		args = append(args, fmt.Sprintf("--vf=fps=%d", p.cfg.MaxFPS))
 	}
 	if p.cfg.Profile != "" && p.cfg.Profile != "low-latency" {
 		args = append(args, "--profile="+p.cfg.Profile)