feat(user): report on another user's time entries

- Add user_id parameter to fetch_issues_with_spent_time().
- Support numeric ID, login, or full name resolution.
- Reject ambiguous names and unknown users with clear messages.
- Add CLI flags: --user-id, --user-login, --user-name.
- Only allow one user flag at a time.
- Add ResourceNotFoundError handling.
- Update README with usage examples.
- Add tests for user resolution and CLI flags.

Closes #40

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "redmine-reporter"
-version = "1.6.1"
+version = "1.7.0"
 description = "Redmine time-entry based issue reporter for internal use"
 readme = "README.md"
 authors = [{ name = "Artem Kokos", email = "artem-kokos@mail.ru" }]