fix(e2e): use correct python binary glob for community sandbox image

The community base sandbox image installs Python via uv at
/sandbox/.uv/python/**/python*, not /usr/bin/python*. Update policy
binary globs in e2e tests and docs to match the actual resolved path.

e2e/python/test_sandbox_policy.py

@@ -51,7 +51,9 @@ def _policy_for_python_proxy_tests() -> sandbox_pb2.SandboxPolicy:
                 endpoints=[
                     sandbox_pb2.NetworkEndpoint(host="api.openai.com", port=443)
                 ],
-                binaries=[sandbox_pb2.NetworkBinary(path="/usr/bin/python*")],
+                binaries=[
+                    sandbox_pb2.NetworkBinary(path="/sandbox/.uv/python/**/python*")
+                ],
             )
         },
     )
@@ -438,7 +440,9 @@ def test_l4_cross_policy_denied(
                 endpoints=[
                     sandbox_pb2.NetworkEndpoint(host="api.anthropic.com", port=443),
                 ],
-                binaries=[sandbox_pb2.NetworkBinary(path="/usr/bin/python*")],
+                binaries=[
+                    sandbox_pb2.NetworkBinary(path="/sandbox/.uv/python/**/python*")
+                ],
             ),
             "other": sandbox_pb2.NetworkPolicyRule(
                 name="other",