Show relative time ("N seconds/minutes ago (at HH:MM)") for recent clips

[faizanafz]

Summary

Adds a relative-time label to the list row timestamp for clips recorded within the last hour. Older items are unchanged.

• just now (at HH:MM) for < 5s
• N seconds ago (at HH:MM) for < 60s
• N minutes ago (at HH:MM) for < 1h
• everything older keeps the existing Today at HH:MM / Yesterday at ... / date formats

The change is contained to clipse_gui/utils.py::format_date. Implemented by checking (now - dt).total_seconds() against 3600 before falling through to the existing date logic, so behavior for non-recent items is byte-identical.

Notes

• The label is computed once when the row is built (same as before), so it does not tick live while the window stays open. Happy to add a periodic refresh if you'd prefer.
• One-hour cutoff is hard-coded as < 3600; can be moved to a config value if useful.

Test plan

• Manually verified with synthetic timestamps at 3s, 25s, 70s, 15min, 59min50s, 2h, and 2d.
• Restarted local clipse-gui and confirmed labels render correctly in the GUI.

[d7omdev]

Thanks for the PR! A few things before merge:

1. Tests fail. test_today_naive, test_z_suffix_treated_as_utc, and test_timezone_aware_iso all assert "Today at " for datetime.now() timestamps, which now fall into the new <3600s branch. They need updating, plus new tests for the boundaries (5s / 60s / 3600s) and singular/plural cases.
2. Label goes stale. format_date runs once at row construction (list_row.py:241). Restoring from the tray (or just leaving the window open) never recomputes it, so "5 seconds ago" can sit there for 10 minutes. Needs a refresh_timestamp() on the row + a GLib.timeout_add_seconds(30, ...) tick while visible + a call on tray restore.
3. Bug: "1 seconds ago" — seconds aren't pluralized like minutes are.
4. Nit: negative delta_seconds (tiny clock skew) silently skips the new branch; consider abs() or treating small negatives as "just now".

Happy to re-review once tests pass and the label refreshes on show.