fix(opencode): patch apiKey from PRAGENT_MODEL_API_KEY at install_config

opencode's @ai-sdk/anthropic provider sends the config's apiKey as the
x-api-key header. The committed opencode.json carries apiKey="ollama"
(placeholder) so the repo can be public. When the headroom upstream
switches to an auth-gated provider (e.g. MiniMax), the placeholder
returns 'No credentials found'. install_config now also patches
options.apiKey from PRAGENT_MODEL_API_KEY when set, mirroring the
existing baseURL patching.

Co-Authored-By: Claude <noreply@anthropic.com>

pilot/opencode_review.py

@@ -406,7 +406,8 @@ def install_config(src: str, dst: str) -> bool:
     if not os.path.isfile(src):
         return False
     base_url = os.environ.get("PRAGENT_MODEL_BASE_URL", "").strip()
-    if not base_url:
+    api_key = os.environ.get("PRAGENT_MODEL_API_KEY", "").strip()
+    if not base_url and not api_key:
         shutil.copy2(src, dst)
         return True
     try:
@@ -414,7 +415,10 @@ def install_config(src: str, dst: str) -> bool:
             cfg = json.load(f)
         for prov in (cfg.get("provider") or {}).values():
             if isinstance(prov, dict) and isinstance(prov.get("options"), dict):
-                prov["options"]["baseURL"] = base_url
+                if base_url:
+                    prov["options"]["baseURL"] = base_url
+                if api_key:
+                    prov["options"]["apiKey"] = api_key
         with open(dst, "w", encoding="utf-8") as f:
             json.dump(cfg, f, indent=2)
     except (OSError, ValueError, AttributeError):