Smoother daemon: no-op reloads, batched placement, muted audio, graceful teardown

- Skip stream restarts when a reload resolves to the identical wall
  (same URLs, tile geometry, player settings) — saving an unrelated
  config edit no longer blanks the screen.
- Replace per-tile placement polling (a swaymsg fork per tile per second,
  plus 150ms get_tree polling per tile at startup) with one shared loop:
  a single get_tree snapshot per tick, re-placing only drifted windows,
  relaxing to a 2s tick once settled.
- Mute streams by default (--no-audio) to skip an audio decoder per
  stream; opt back in with player.audio: true.
- Graceful, parallel mpv teardown via cmd.Cancel/WaitDelay, fixing the
  double-Wait race between Stop and Supervise and cutting worst-case
  layout switches from ~2s x N streams to ~2s total.
- status: probe mpv IPC outside the daemon mutex so a slow probe can't
  block layout switches.
- View sync: reuse the Protect session across ticks (re-login only on
  expiry) and pick up view_refresh_seconds changes without a restart.
- Health strikes keyed by player, not slot, so they never carry across
  layout switches; prune stale entries.
- New `rtsp-streamer reload` CLI; fix dead sort in `layout ls`; back off
  on persistent control-socket accept errors; fsync config before the
  atomic rename (SD-card power-cut safety); bump IPC client deadline;
  gofmt stragglers.

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

config.example.yaml

@@ -20,6 +20,8 @@ player:
                                # won't engage it; "no" forces software.
   profile: low-latency
   max_fps: 0                   # cap rendered fps (0 = uncapped); trims render load
+  audio: false                 # streams are muted by default (saves CPU too);
+                               # set true to decode and play camera audio
   restart_backoff_seconds: 3
   extra_args: []