fix: PR #107 review fixes — cron cadence + gateway log health check

FAIL 1: Cron cadence was */10 * * * * (every 10 min) but the real crontab
on CT 100 is 35 2,6,10,14,18,22 * * * (every 4 hours at :35). Fixed in
frontmatter, body, and Continuity section. Added 4-hour rationale note.

FAIL 2: Added gateway log health to the list of checks (frontmatter +
Strategies section). Added note that script may perform additional
diagnostics beyond the seven contract checks.

agent-health-check.prose.md

@@ -3,11 +3,11 @@ kind: responsibility
 name: agent-health-check
 description: >
   Consolidated agent health verification for the LiteLLM + GPU + Zulip +
-  gateway fleet. Wraps scripts/agent-health-check.py (v4). Runs every
+  gateway fleet. Wraps scripts/agent-health-check.py (v4). Runs every 4 hours
-  10 minutes via cron and on-demand via "run contract: agent-health-check".
+  via cron and on-demand via "run contract: agent-health-check". Verifies:
-  Verifies: LiteLLM key validity, GPU port conflicts, agent Zulip streaming,
+  LiteLLM key validity, GPU port conflicts, agent Zulip streaming, gateway
-  gateway liveness, CT liveness, config YAML integrity, wrapper/CLI integrity,
+  liveness, CT liveness, gateway log health, config YAML integrity,
-  vault secret non-emptiness. NEVER restarts anything.
+  wrapper/CLI integrity, vault secret non-emptiness. NEVER restarts anything.
 title: Agent Health Check — Consolidated
 version: 1.0.0
 runtime_contract: 2
@@ -17,8 +17,9 @@ agent: abiba
 # Agent Health Check
 
 Consolidated health verification for the LiteLLM + GPU + Zulip + gateway fleet.
-Runs every 10 minutes via cron (`*/10 * * * *`) and on-demand. Never restarts
+Runs every 4 hours (2, 6, 10, 14, 18, 22 UTC at :35) via cron (`35 2,6,10,14,18,22 * * *`) and on-demand. Never restarts anything — detects and reports only.
-anything — detects and reports only.
+
+**Cadence rationale** (2026-08-28 decision): monitoring dispatches moved from hourly to every 4 hours to reduce probe load on GPU hosts while keeping detection latency acceptable (up to 4 hours).
 
 ## Requires
 
@@ -91,8 +92,13 @@ Report the specific CT. Do not restart — that's a destructive action.
 ### When config YAML is invalid
 Report the specific file + parse error. Do not fix — that's a config change.
 
+### When gateway log health is degraded
+Report the specific gateway + log health status (error patterns, stale connections, connectivity issues). Do not restart — that's a destructive action.
+
+Note: the script may perform additional diagnostics beyond the seven contract checks listed under Execution.
+
 ## Continuity
 
-- **Every 10 minutes**: Scheduled cron check while Abiba is running
+- **Every 4 hours** (2, 6, 10, 14, 18, 22 UTC at :35): Scheduled cron check while Abiba is running
 - **On `agent-health` command**: Run on-demand and report to user
 - **On critical alert**: Escalate to relay message immediately