fix(health): suppress 404 when health monitor disabled + fix audit test assertion

- Sidebar.svelte: defer healthStore.refresh() until feature flags confirm
  health_monitor is enabled; skip entirely when disabled
- health.js: remove throw error from catch block — log and return null
  instead, preventing 'Uncaught (in promise)' on expected 404
- test_report_audit_immutability.py: fix mock assertions —
  audit_service uses logger.reason/reflect/explore, not logger.info
- HealthStore and Sidebar now produce zero network noise when
  FEATURES__HEALTH_MONITOR=false

.opencode/agents/reflection-agent.md

@@ -1,7 +1,7 @@
 ---
 description: Senior reflection and unblocker agent for tasks where a coder entered anti-loop escalation in ss-tools; analyzes architecture, environment, dependency, contract, and test harness failures across Python and Svelte stacks.
 mode: subagent
-model: opencode-go/mimo-v2.5
+model: opencode/big-pickle
 temperature: 0.0
 permission:
   edit: allow