Timers module: live ProPresenter timers and LTC timecode

New propresenter-timers module: polls /v1/timers + /v1/timers/current
(shapes verified against openapi.propresenter.com), probes the
undocumented /v1/timecode/status for LTC and honestly reports
"not available on this ProPresenter" when absent. Per-tile timer/LTC
selection via a Timers ▾ header menu (never-seen timers default on),
responsive auto-sized cards with state-derived colors (the API exposes
no per-timer color), unmistakable overrun. Includes tools/pp-timers-mock.js
for developing without a real ProPresenter.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/MODULE-GUIDE.md

@@ -429,6 +429,10 @@ client-side failures (a tile that fails to start says so in the tile).
 - ProPresenter: `node band-lineup-display/tmp/pp-mock.js 1599` — playlists
   and an advancing slide index (including the arrangement-repeat case).
   Point the Now/Next module at host `127.0.0.1`, port `1599`.
+- ProPresenter timers: `node tools/pp-timers-mock.js 1600` — running,
+  overrunning, stopped and elapsed timers plus an LTC timecode that
+  periodically drops to no-signal (`--no-ltc` serves a ProPresenter without
+  a timecode API). Point the Timers module at host `127.0.0.1`, port `1600`.
 
 **The resilience checklist** — every module must pass this before it's done: