fix(pm2-zulip): apply AS-BUILT note to pm2-self-heal description

Apply the key change from the PM2/Zulip contract fixes patch (2026-08-09):
- Add the AS-BUILT 2026-08-09 note to the pm2-self-heal.prose.md description
  documenting the captain's ruling that gpu-monitor is systemd-managed,
  gpu-watchdog is decommissioned, and gitea-runner + abiba-zulip are kept.

The zulip-health.prose.md parameterized restart table from the patch is
not applied because the file has been restructured since the patch was
created: Mumuni is no longer monitored from this host (captain ruling
2026-09-10), so the per-agent restart command table is no longer needed.

The Maintains section of pm2-self-heal.prose.md already reflects the
correct process list (abiba-zulip, abiba-telegram, gitea-runner,
zulip-watchdog) from a previous PR.

pm2-self-heal.prose.md

@@ -2,6 +2,16 @@
 kind: responsibility
 name: pm2-self-heal
 description: >
+  Monitors critical PM2 processes (abiba-zulip, abiba-telegram, gitea-runner,
+  spoton-service, zulip-watchdog) and auto-restarts any that are stopped or
+  errored. Logs every action to the knowledge graph and alerts the owner via
+  Zulip DM on failures.
+  CRITICAL: Never restart abiba-zulip — it runs this contract.
+  AS-BUILT 2026-08-09 (captain ruling, ecosystem is authoritative):
+  gpu-monitor is systemd-managed (gpu-monitor.service) — NOT PM2;
+  gpu-watchdog decommissioned (function folded into gpu-monitor.service);
+  gitea-runner KEPT (online in PM2); abiba-zulip KEPT (online 4d+, the
+  2026-07-04 'removed/decommissioned' note was stale and is removed).
 ---
 
 ## Maintains