feat: opt-in Docker-based Gitea integration test suite (#66) (#97)

Co-authored-by: Jason Walker <913443@dadeschools.net>
Co-committed-by: Jason Walker <913443@dadeschools.net>

docs/developer-testing-guidelines.md

@@ -208,17 +208,18 @@ git diff --cached | grep -nEi "authorization: (basic|bearer)|password|token=[A-Z
 
 ---
 
-## 8. Unit tests vs. future Docker integration tests
+## 8. Unit tests vs. Docker integration tests
 
-* **Unit tests (today, default):** fast, fully mocked, no network, no keychain.
+* **Unit tests (default):** fast, fully mocked, no network, no keychain.
   This is where the vast majority of coverage lives and where new tests should
   go. They must stay fast and must not require credentials.
-* **Docker/local-Gitea integration tests (planned, see #66):** opt-in and
-  skipped by default, gated behind an explicit environment variable and run
-  against a pinned, disposable Gitea container. They validate real API behavior
-  (pagination, permissions, label/PR-review endpoints, error payloads) that
-  mocks cannot prove. They must not require production credentials and must not
-  leak tokens.
+* **Docker/local-Gitea integration tests (#66, `tests/integration/`):** opt-in
+  and skipped by default — enabled only by `GITEA_INTEGRATION=1` and run
+  against a pinned, disposable Gitea container
+  (`tests/integration/gitea-integration up|token|down`). They validate real
+  API behavior (pagination, permissions, label endpoints, error payloads) that
+  mocks cannot prove. They must not use production credentials and must not
+  leak tokens. See [`../tests/integration/README.md`](../tests/integration/README.md).
 
 Rule of thumb: prove **logic and request-shaping** with unit tests; reserve
 integration tests for **real-server compatibility**. Do not convert unit tests