chore(skills): promote runbook skills to managed-skills; drop superseded SKILL.md

- 31 new managed skills (anubis/arr/authentik/hermes/freetoken/podman/llm-swap
  runbooks etc.) now tracked.
- Removed superseded skills: omp_harness_config, peon_ping_integration
  (replaced by user-authored peon-ping-* managed skills),
  rocmfp4-strix-benchmark-orchestration.
- New memory-root skills: niri_compositor_ops, omp_git_workflow,
  omp_model_config, quadlet-media-migration, homelab-service-triage,
  hermes-dankclaw-ops, frank-default-large-ops, caddy-auth-dns-playbook.

agent/managed-skills/imagegen-openwebui/SKILL.md

@@ -0,0 +1,43 @@
+---
+name: imagegen-openwebui
+description: Runbook for running high-quality local image generation via Open WebUI imagegen API endpoint.
+---
+
+# Open WebUI Image Generation Runbook
+
+## Overview
+Use this procedure to generate images locally using the Open WebUI image generation endpoint.
+This approach leverages local ComfyUI integration configured in Open WebUI.
+
+## Endpoint
+POST to the imagegen endpoint of your Open WebUI instance.
+
+### Example Request
+```python
+import requests
+
+url = "http://<host>:<port>/api/images/generations"
+headers = {"Authorization": "Bearer <your_token>"}
+data = {
+    "model": "imagegen",
+    "prompt": "A desired image description.",
+    "n": 1,
+    "size": "1024x1024"
+}
+
+response = requests.post(url, headers=headers, json=data)
+```
+
+### Example Response
+Returns an object with base64-encoded image data or a URL.
+
+## Best Practices
+- Keep prompts descriptive for best results.
+- Use the default model unless configured otherwise.
+- Verify that ComfyUI is running and connected before invoking.
+- Check Open WebUI logs for troubleshooting if generation fails.
+
+## Common Issues
+- **Connection refused**: Ensure Open WebUI and ComfyUI are running.
+- **Timeout errors**: Large image sizes may take longer; check ComfyUI resources.
+- **Authentication errors**: Verify API token validity in the request headers.