feat(gpu-fleet): GPU fleet management prose contract

Declarative GPU roster replaces hardcoded router.py model configs.
Operations: add-model, remove-model, heal, sync-keys, list.
Documents agent key architecture with LITELLM_API_KEY env var.
Covers all 3 GPU hosts (RTX 5070, RTX 3090, Strix Halo).

gpu-fleet.prose.md

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+---
+kind: responsibility
+name: gpu-fleet
+description: >
+  Manages the GPU inference fleet across all hosts. Handles model deployment,
+  registration, hot-reload, health checks, LiteLLM sync, agent key management,
+  and stale model cleanup. Replaces hardcoded router.py config with declarative
+  gpu_roster.yaml.
+agent: abiba
+triggers:
+  - on model add/remove
+  - on GPU health degradation
+  - on agent key rotation
+---
+
+## Maintains
+
+- gpu_roster: { models: map, hosts: map } — Single source of truth for all GPU models
+- router: { status: "healthy", models: array }
+- litellm: { status: "healthy", models: array }
+- agent_keys: { agent: api_key } — All agent API keys registered in LiteLLM DB
+- health: { gpus: array, circuit_breakers: array }
+
+## Operations
+
+### add-model
+1. Download model file from Hugging Face or source
+2. Check disk space + GPU VRAM compatibility
+3. Build/update llama.cpp if needed (cmake, Vulkan/CUDA flags)
+4. Start llama-server via systemd service
+5. Add to `gpu_roster.yaml`
+6. Hot-reload router: `POST /admin/roster/reload`
+7. Sync LiteLLM config: add model to model_list + fallbacks
+8. Generate/update agent keys for new model access
+9. Verify end-to-end: LiteLLM → Router → Model
+
+### remove-model
+1. Drain active requests (wait for active=0)
+2. Update `gpu_roster.yaml` — remove entry
+3. Hot-reload router
+4. Remove from LiteLLM config
+5. Stop llama-server (systemd)
+6. Cleanup model files (optional — keep if model might return)
+
+### heal
+1. Check all GPUs via router `/health/unified`
+2. Reset stuck circuit breakers if idle
+3. Restart dead llama-server instances
+4. Flush Redis counters if stale
+5. Sync LiteLLM if configs diverge
+
+### sync-keys
+1. List all agent keys in LiteLLM DB via `/key/list`
+2. Compare against expected agent list
+3. Generate missing keys via `/key/generate`
+4. Update agent configs to use `api_key_env: LITELLM_API_KEY`
+5. Set `LITELLM_API_KEY` in system-wide env + startup wrapper
+6. Restart gateways
+
+### list
+Show full fleet status: GPUs, models, VRAM, active requests, circuit breakers
+
+## Configuration Files
+
+| File | Host | Purpose |
+|------|------|---------|
+| `gpu_roster.yaml` | CT 116 (`/opt/inference-harness/`) | Model-to-GPU mapping |
+| `litellm_config.yaml` | CT 116 | LiteLLM proxy config |
+| `roster_loader.py` | CT 116 (router container) | Hot-reloadable roster parser |
+| `/etc/systemd/system/moe-server.service` | .15 | Ornith-1.0-35B server |
+| Agent configs | .122, .123, .114 | `api_key_env: LITELLM_API_KEY` |
+
+## GPU Fleet Topology
+
+```
+┌──────────────────────────────────────────────────┐
+│  LiteLLM (:4001)                                 │
+│  Config: /opt/inference-harness/litellm_config.yaml │
+└──────────────┬───────────────────────────────────┘
+               │
+┌──────────────▼───────────────────────────────────┐
+│  Router (:9000)                                   │
+│  Roster: /app/gpu_roster.yaml (hot-reload)       │
+│  Redis: slot booking + circuit breakers          │
+└──────┬──────────┬──────────┬─────────────────────┘
+       │          │          │
+  ┌────▼───┐ ┌───▼────┐ ┌──▼──────┐
+  │ gemma  │ │ qwen   │ │ ornith  │
+  │ 4-12b  │ │ 27B    │ │ 1.0-35B │
+  │ .110   │ │ .8     │ │ .15     │
+  │ 5070   │ │ 3090   │ │ Strix   │
+  └────────┘ └────────┘ └─────────┘
+```
+
+## Agent Key Architecture
+
+All agents use `api_key_env: LITELLM_API_KEY` in Hermes configs:
+
+| Agent | Host | Config | Env Source |
+|-------|------|--------|------------|
+| Mumuni | .123 | 7 refs + 6 subagent profiles | `/etc/environment` + wrapper |
+| Tanko | .122 | 4 refs | `/etc/environment` + wrapper |
+| Koonimo | .114 | 5 refs | `/etc/environment` + wrapper |
+
+To rotate all keys: update `LITELLM_API_KEY` value, restart gateways.
+
+## Sync Protocol
+
+1. Edit `gpu_roster.yaml` → `POST /admin/roster/reload` (hot, no restart)
+2. Edit `litellm_config.yaml` → `docker restart harness-litellm`
+3. Agent key changes → generate via `POST /key/generate` with master key