feat: initial OpenProse contracts — LiteLLM health check + hello world

- litellm-health.prose.md: Verifies admin UI, API docs, OIDC auth, container
  health, and aggregate health endpoint. Reusable by any Syslog agent.
- hello-world.prose.md: Simple example contract demonstrating OpenProse
  function pattern with parameters, returns, and postconditions.

litellm-health.prose.md

@@ -0,0 +1,56 @@
+---
+kind: function
+name: check-litellm-health
+description: >
+  Verifies LiteLLM deployment is healthy by checking admin UI, API docs,
+  OIDC auth endpoint, container status, and aggregate health on the
+  backend host. Designed as a reusable contract for any Syslog agent.
+---
+
+## Parameters
+
+- public_url: string — The public LiteLLM URL (default: "https://litellm.sysloggh.net")
+- backend_host: string — Internal CT host to check containers (default: "192.168.68.116")
+- auth_host: string — Authentik server for OIDC (default: "192.168.68.11")
+
+## Returns
+
+- overall_status: "healthy" | "degraded" | "down"
+- checks: array of { name: string, status: string, detail: string }
+- timestamp: string — ISO timestamp of the check run
+- duration_ms: number — How long the check took
+
+## Requires
+
+- SSH key access to backend_host for container checks
+- Network access to public_url and auth_host
+- curl and openssl available on the execution host
+
+## Ensures
+
+- Each check returns a clear pass/fail status with detail message
+- If any endpoint returns non-200, overall_status is "degraded"
+- If backend host unreachable or >2 containers down, overall_status is "down"
+- If /health/unified reports any non-healthy components, status reflects it
+- Checks cover at minimum: admin UI, API docs, OIDC, containers, unified health, nginx proxy
+
+## Execution
+
+1. **Read parameters** — Use provided values or defaults
+2. **Check public endpoints**:
+   - GET {{public_url}}/ui/ → expect 200 ("LiteLLM Dashboard")
+   - GET {{public_url}}/docs → expect 200 ("LiteLLM API - Swagger UI")
+   - GET {{public_url}}/openapi.json → expect 200 (valid JSON, 497 paths)
+   - GET {{public_url}}/redoc → expect 200 ("LiteLLM API - ReDoc")
+3. **Check nginx-proxied endpoints** (internal only — Netbird routes to LiteLLM directly):
+   - GET http://{{backend_host}}/litellm/ui/ → expect 200
+   - GET http://{{backend_host}}/litellm/docs → expect 200
+4. **Check aggregate health endpoint**:
+   - GET {{backend_host}}:9000/health/unified → expect 200, check all components
+5. **Check backend container health**:
+   - SSH to {{backend_host}} → `docker ps` → verify all 6 containers are healthy
+   - Containers: harness-litellm, harness-nginx, harness-router, harness-postgres, harness-redis, harness-dashboard
+6. **Check OIDC auth endpoint**:
+   - Verify auth.sysloggh.net resolves to {{auth_host}}
+   - GET https://auth.sysloggh.net/ → expect login page
+7. **Compile and report** — Determine overall_status from individual check results