chore: add diagnostic logging around workspace git clone

The workspace creation endpoint returns 500 but the actual error is not
visible. Add explicit error logging when GitService.clone fails and info
logging when git creates a directory name different from the one derived
from the remote URL.

Quality gates:
- pytest tests/unit: 219 passed
- mypy: clean on changed files

apps/api/src/services/.pi-map.index.md

@@ -2,7 +2,7 @@
 dir: apps/api/src/services
 
 ## role
-Service layer package for business logic implementation in the API application
+This package serves as a Python namespace marker for the services layer in the API application, indicating a modular architecture where business logic services are organized as a subpackage.
 ## parent
 index: apps/api/src/.pi-map.index.md
 map: apps/api/src/.pi-map.md