Cursor-scoped activity log follows the table cursor

[iTerminate]

Summary

• Moving the table cursor while a "Selected entity" / "Selected entity's device" scoped activity log is open now re-titles, refetches, and (when live) resubscribes automatically, instead of requiring the user to re-press v and re-pick the scope.
• Debounced (0.3s) so held arrow-key repeats coalesce into one refetch; skipped while the log panel is maximized, since the table isn't what's focused there.

Test plan

• pytest tests/unit/test_logbook_controller.py tests/test_activity_log.py tests/test_device_log.py tests/test_log_scope_popup.py tests/test_log_maximize.py tests/test_graph_event_log.py tests/test_graph_log_maximize.py
• Full pytest suite (1285 passed)
• uv run ruff check .
• uv run pyright

Refs #38