Squash of the 54 commits on victor-kyriazakos:feat/user-channel-warning-suppression
(PR #112302, head f45c640e55) so the contributor's authorship survives a rebase-merge;
the commits interleave with a cron delivery-ledger rework that the salvage removes in
follow-up commits, so per-commit cherry-picks were not practical.
Adds display.suppress_warning_notifications (global + per-platform, default false):
one resolver (gateway/warning_notifications.py), BasePlatformAdapter.emit_warning /
emit_media_warning / warning_text, a notification_category classification carried
through wakes, queues and persistence, and render/present boundaries for CLI/TUI.
cd3de040ab