fix: Slim down nox pydantic-v1 test session

The test-pydantic-v1 nox session was installing from requirements-dev.lock
which includes heavy dependencies like torch (900MB). This exhausted disk
space on GitHub Actions runners.

Changed to install only the core SDK and minimal test dependencies:
- Core SDK package (editable install)
- pydantic<2 for compatibility testing
- pytest, pytest-asyncio, respx for test execution
- time-machine, dirty-equals for test fixtures

This reduces install size significantly and prevents "No space left on device" errors.

noxfile.py

@@ -3,7 +3,18 @@ import nox
 
 @nox.session(reuse_venv=True, name="test-pydantic-v1")
 def test_pydantic_v1(session: nox.Session) -> None:
-    session.install("-r", "requirements-dev.lock")
-    session.install("pydantic<2")
+    # Install only the core SDK package and test dependencies
+    # Avoids installing heavy dependencies like torch (900MB) that would exhaust disk space
+    session.install("-e", ".")
+    session.install(
+        "pydantic<2",
+        "pytest",
+        "pytest-asyncio",
+        "respx",
+        "time-machine",
+        "dirty-equals>=0.6.0",
+        "importlib-metadata>=6.7.0",
+        "rich>=13.7.1",
+    )
 
     session.run("pytest", "--showlocals", "--ignore=tests/functional", *session.posargs)