fix(fmcd): cap CPU + watchdog-restart the iroh relay hot-loop

On NAT'd nodes that can reach the iroh federation neither directly nor
via iroh's public relays, fmcd's embedded iroh networking enters a
relay/hole-punch reconnect hot-loop that pegs its entire CPU allotment
indefinitely (observed ~1 core sustained for 4 days on a Tailscale node,
while LAN nodes that reach the guardian directly stay <3%). fmcd 0.8.0
exposes no iroh/relay knobs, so:

- fmcd-run now samples fmcd's own CPU and restarts it when it stays near
  its allotment for ~15 min (a restart demonstrably clears the stuck iroh
  state; real work is bursty and never flat-pegs a core for minutes).
- Lower cpu_limit 1 -> 0.25 core so a stuck instance can't starve the
  node (steady-state is <3% of a core; joins are brief).

Ships as fmcd:0.8.1 (launcher-only rebuild, same fmcd binary). Bumped the
image pin + cpu_limit in the manifest, image-versions.sh, the embedded
catalog manifest (releases/app-catalog.json), and the UI catalogs.

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

neode-ui/public/catalog.json

@@ -274,7 +274,7 @@
       "author": "Fedimint",
       "category": "money",
       "tier": "core",
-      "dockerImage": "146.59.87.168:3000/lfg2025/fmcd:0.8.0",
+      "dockerImage": "146.59.87.168:3000/lfg2025/fmcd:0.8.1",
       "repoUrl": "https://github.com/minmoto/fmcd"
     },
     {