chore: give the package page a body and repo links

1.1.2 went out with an empty description on the registry page: without a
readme field there is no long_description, and twine only warns about
that -- it does not block the upload. Add readme and project.urls, and
record the wider lesson in the release procedure: a release is done when
the pages a downstream user actually opens look right, not when the local
steps go green. Also adds the missing step for creating a Release, which
is why the Releases page sat empty through eight tags.

pyproject.toml

@@ -6,6 +6,9 @@ build-backend = "setuptools.build_meta"
 name = "polygateway"
 version = "1.1.2"
 description = "PolyGateway：实验室统一的大语言模型（LLM/VLM/OCR）调度与中转库——多源、限流、重试、熔断、缓存、遥测"
+# registry 包页面的正文只认这一项:缺了页面就是一片空白(1.1.2 的教训,twine 会警告
+# long_description missing 但不阻塞上传)。README 在打包时被固化进产物,发布后再改无效。
+readme = "README.md"
 requires-python = ">=3.11"
 dependencies = [
     "httpx>=0.27",
@@ -31,6 +34,11 @@ dev = [
     "import-linter>=2.0",
 ]
 
+[project.urls]
+Homepage = "https://gitea.iomgaa.online/iomgaa/PolyGateway"
+Changelog = "https://gitea.iomgaa.online/iomgaa/PolyGateway/src/branch/main/CHANGELOG.md"
+Issues = "https://gitea.iomgaa.online/iomgaa/PolyGateway/issues"
+
 [tool.setuptools.packages.find]
 where = ["src"]