fix: align dependency-groups with r-dev to avoid TOML duplicate key

r-dev already has [dependency-groups] with dev deps including pytest
and pytest-asyncio. Our branch had a different structure causing a
duplicate key error when merged. Align with r-dev's format.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pyproject.toml

@@ -43,12 +43,11 @@ dependencies = [
 ]
 
 [dependency-groups]
-test = [
-    "pytest>=8.4.1",
-    "pytest-asyncio>=1.1.0",
-]
 dev = [
-    { include-group = "test" },
+    "pytest",
+    "pytest-asyncio",
+    "ruff>=0.12.2",
+    "zstandard",
 ]