add reset clock display toggle

[aliibarznji]

Summary

Adds a reset-time display toggle to the taskbar widget. By default, usage rows keep showing the existing relative reset countdown, such as 2h or 14m. Clicking the usage text area toggles the reset label to a local 12-hour clock time, such as 8:22, and clicking again switches back.

The selected display mode is saved in %APPDATA%\ClaudeCodeUsageMonitor\settings.json as reset_time_display, so the preference survives app restarts.

Notes

• Keeps the existing relative countdown behavior as the default.
• Uses the existing reset SystemTime values already returned by the usage poller.
• Converts reset times to local Windows time before formatting as h:mm without an AM/PM suffix.
• Adds a hand cursor over the clickable reset text area.

Validation

• git diff --check
• cargo test