fix: export path_template from _utils (#330)

## Summary
- `_utils/_path.py` defines `path_template` which is imported by
multiple resource modules (admin, benchmarks, eval, models, etc.)
- `_utils/__init__.py` was missing the re-export, causing `ImportError:
cannot import name 'path_template' from 'llama_stack_client._utils'` at
import time
- This breaks llama-stack CI (`client=latest` variant) and anyone
installing from git main

## Test plan
- [x] Verify `from llama_stack_client._utils import path_template` works
- [ ] Verify llama-stack integration tests pass with `client=latest`

Signed-off-by: Charlie Doern <cdoern@redhat.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: cdoern

src/llama_stack_client/_utils/__init__.py

@@ -4,6 +4,7 @@
 # This source code is licensed under the terms described in the LICENSE file in
 # the root directory of this source tree.
 
+from ._path import path_template as path_template
 from ._sync import asyncify as asyncify
 from ._proxy import LazyProxy as LazyProxy
 from ._utils import (