backport: coverage — raise dev-dep floors for tests/interaction (pytest 8.4, sse-starlette 2.1)

lowest-direct only; runtime floors unchanged.

- pytest>=8.4.0: tests/interaction/auth uses pytest.RaisesGroup (8.4+); matches main.
- sse-starlette>=2.1.0 (dev group): 1.x keeps a module-global anyio.Event
  (AppStatus.should_exit_event) bound to the first test's event loop, which breaks
  every subsequent in-process SSE response under the streaming bridge. v1's own
  tests run uvicorn in a subprocess so don't observe this. Runtime floor stays
  >=1.6.1 (the SDK works with 1.6.1 under uvicorn).

Author: maxisbey

pyproject.toml

@@ -53,7 +53,7 @@ required-version = ">=0.9.5"
 [dependency-groups]
 dev = [
     "pyright>=1.1.400",
-    "pytest>=8.3.4",
+    "pytest>=8.4.0",
     "ruff>=0.8.5",
     "trio>=0.26.2",
     "pytest-flakefinder>=1.1.0",
@@ -63,6 +63,11 @@ dev = [
     "inline-snapshot>=0.23.0",
     "dirty-equals>=0.9.0",
     "coverage[toml]==7.10.7",
+    # tests/interaction runs the streamable-HTTP and SSE apps in-process; sse-starlette 1.x
+    # keeps a module-global anyio.Event (`AppStatus.should_exit_event`) bound to the first
+    # test's event loop, which breaks every subsequent in-process SSE response. The runtime
+    # floor stays >=1.6.1 (works under uvicorn); only the test environment needs >=2.x.
+    "sse-starlette>=2.1.0",
 ]
 docs = [
     "mkdocs>=1.6.1",