fix: allow Jira completion without loggable tracked time

[cbartz]

et jira complete currently aborts before its cleanup and Done prompts when the workspace has less than 60 seconds tracked, including zero, or has no prepared counter. For example, completing after 25 seconds fails with the minimum-time logging error.

Allow completion to skip the worklog in those cases and continue to both confirmation prompts. Report that logging was skipped, and preserve a short counter if workspace deletion is declined. Counters at or above 60 seconds are logged as before. Standalone jira log-time validation and other extension/API errors remain unchanged.

Validation:

• 509 Python tests pass (89.30% coverage), including completion with a missing counter and 0, 25, 59, and 60 seconds, with both accepted and declined prompts.
• Ruff, mypy, ShellCheck, extension metadata validation, and schema validation pass.
• GNOME JavaScript tests could not run because gjs is unavailable. Manual verification in GNOME is pending.

CI also exposed a repeatable temporary-directory cleanup failure on GNOME 50 after all live D-Bus checks passed. Cleanup now retries removal up to three times to tolerate portal shutdown races, rechecking the mount guards before each attempt. Regression tests verify recovery after a transient removal failure and a nonzero exit after persistent failures. Updated Python suite: 509 tests pass.