Timers 1.5.0: the LTC capture tool installs itself; tiles warn in one line

A catalog install ships source only, and a catalog update deletes the
module folder — a previously built ltc-capture binary with it — so every
install or update left LTC dead until someone compiled the tool by hand.
The build also still used the blocking spawnSync that once froze the whole
server (the bug spl-meter fixed in 0.4.0), and only ran when a listener
started: no tool meant no device list, and no device meant no listener.

ensureCaptureBinary() (module scope in ltc-listener.js, the spl-meter
0.4.2 pattern) now builds the tool in the background as part of coming
up: kicked when the LTC source starts and by the admin device picker,
single-flight, built to a temp name and renamed so a killed build can't
leave a truncated binary, and rebuilt behind a still-serving binary when
a module update leaves the source newer. The waiting listener starts
itself the moment the build lands.

Tile-side warnings are now one line — 'Not configured — see Admin',
'Unreachable', 'Capture tool building…' — with the client's source-label
prefix no longer repeated. The full diagnostics (host:port, errno, the
capture tool's own words, build instructions) move to the admin health
line and the log, where the person who can act on them is looking.

Verified: build from the exact catalog-install state (source only) lands
and lists 12 real devices; touching the source triggers an atomic rebuild
while the old binary keeps serving; /ltc/devices kicks the build and
answers with the device list; live server shows terse source messages on
the tile and the detailed story in /api/admin/state health. ltc and phase
selftests still pass.

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

modules/propresenter-timers/module.json

@@ -1,7 +1,7 @@
 {
   "id": "propresenter-timers",
   "name": "Timers",
-  "version": "1.4.2",
+  "version": "1.5.0",
   "proddash": ">=1.4.0",
   "description": "Timers, Clocks, and LTC From configured Modules",
   "provides": [