ductor v0.6.2

Fixes cron job results not being delivered to Telegram, and Windows upgrade PermissionError.

Cron result delivery fix

Cron job results were silently dropped under two conditions:

Race condition: Result delivery happened AFTER update_run_status() wrote to cron_jobs.json. The file-watcher could detect the change, trigger a reschedule, and cancel the running task — before the Telegram message was sent. Results are now delivered before the file write.
Deleted job guard: if self._on_result and job: silently dropped results when get_job() returned None (e.g., after a manager reload). Removed the job dependency — delivery now uses the title captured at execution start.
Unhandled exceptions: _run_at only caught CancelledError, so any unexpected exception in _execute_job silently lost the result and prevented rescheduling. Now catches and logs all exceptions.

4 new tests verify these scenarios.

pipx upgrade fails on Windows with PermissionError because the running bot process locks ductor.exe.

Windows: Uses pipx runpip instead of pipx upgrade to upgrade inside the venv without touching the locked global exe.
Always verify version: Checks installed version after upgrade regardless of exit code — pipx may report failure from exe lock while the package is actually upgraded.
CDN propagation hint: When pip can't find the pinned version, shows a user-friendly message instead of raw pip error.

ductor upgrade
# or
pip install --upgrade ductor