Address PR feedback: keep testEnvironment non-destructive, warn on swallowed errors

- Update cwd test to expect an error for missing directories (matches
  createIfMissing: false accepted from review)
- Add warn-level check for non-ProviderModelNotFoundError failures
  during best-effort model discovery when no model is configured

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/adapters/opencode-local/src/server/test.ts

@@ -180,6 +180,13 @@ export async function testEnvironment(
           detail: errMsg,
           hint: "Run `opencode models` and choose an available provider/model ID.",
         });
+      } else {
+        checks.push({
+          code: "opencode_models_discovery_failed",
+          level: "warn",
+          message: errMsg || "OpenCode model discovery failed (best-effort, no model configured).",
+          hint: "Run `opencode models` manually to verify provider auth and config.",
+        });
       }
     }
   }