test: add MCP smoke tests over stdio and streamable HTTP, from source and from the built image

pyproject.toml

@@ -86,6 +86,10 @@ ignore = [
     "B008",  # function calls in argument defaults (pydantic Field style)
 ]
 
+[tool.ruff.lint.isort]
+# tests/mcp is a directory, not the SDK: keep "mcp" classified as third party.
+known-third-party = ["mcp"]
+
 [tool.ruff.lint.per-file-ignores]
 "__init__.py" = ["F401"]
 "tests/integration/harness.py" = [
@@ -129,6 +133,7 @@ pythonpath = ["src"]
 asyncio_mode = "auto"
 markers = [
     "integration: needs a live Gitea in Docker (opt-in via AEGIS_INTEGRATION=1)",
+    "mcp_smoke: MCP client smoke tests over real transports (opt-in via AEGIS_INTEGRATION=1)",
 ]
 
 [tool.coverage.run]