feat(ai_review): route per-repo model override through PRICES provider field

pilot/ai_review.py

@@ -483,11 +483,15 @@ def _resolve_display_model(base_model: str, config: dict | None) -> str:
 
     Precedence (highest first):
       1. `OPENCODE_MODEL` env var — operator override, used as-is (already a
-         provider-prefixed opencode ref).
+         provider-prefixed opencode ref like `headroom/MiniMax-M2.7`).
       2. `.pr-review.json:model` — per-repo override. Already validated
          against `cost_model.PRICES` by `parse_repo_config`, so a bare key
-         like `claude-sonnet-5` is safe to use as the opencode ref AND the
-         REVIEW_HEADER label.
+         like `claude-sonnet-5` or `qwen3.8-27b` is safe. Re-prefixed with
+         the model's `provider` field from `cost_model.Price` (default
+         `headroom`) so the opencode subprocess routes correctly — e.g.
+         `qwen3.8-27b` → `local/qwen3.8-27b` (local AI workstation on
+         192.168.1.79:18020), `claude-sonnet-5` → `headroom/claude-sonnet-5`
+         (Anthropic pricing proxy).
       3. Default — `f"headroom/{base_model}"` where `base_model` is the bare
          `OLLAMA_MODEL` (e.g. `"MiniMax-M2.7" → "headroom/MiniMax-M2.7"`).
 
@@ -500,7 +504,16 @@ def _resolve_display_model(base_model: str, config: dict | None) -> str:
         return env
     cfg_model = (config or {}).get("model")
     if isinstance(cfg_model, str) and cfg_model.strip():
-        return cfg_model.strip()
+        # Look up the provider from PRICES so the opencode subprocess routes
+        # through the right provider block (local vs headroom). Lazy import —
+        # the ollama path doesn't touch cost_model.
+        from cost_model import PRICES
+        provider = PRICES.get(cfg_model.strip())
+        if provider is not None:
+            return f"{provider.provider}/{cfg_model.strip()}"
+        # parse_repo_config already drops unknowns, but stay defensive: fall
+        # back to headroom so the review still runs rather than crash.
+        return f"headroom/{cfg_model.strip()}"
     return f"headroom/{base_model}"