feat(opencode): add oh-my-openagent plugin with omo config for ollama-cloud/glm-5.1

Configure oh-my-openagent (omo) plugin for multi-agent orchestration
using ollama-cloud and local llama-swap providers. Primary model is
ollama-cloud/glm-5.1 with fallback chains. Add runtime fallback,
background task concurrency limits, and disable incompatible agents
(hephaestus, multimodal-looker).

home/roles/base/opencode-config.json

@@ -1,5 +1,6 @@
 {
   "$schema": "https://opencode.ai/config.json",
+  "plugin": ["oh-my-openagent"],
   "provider": {
     "llama-local": {
       "name": "Llama.cpp (zix790prors RTX 4070 Ti)",