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.
Squashed integration of the user-facing message audit for this surface set.
Full per-finding receipts: /tmp/ux-audit/lanes/*-receipt.md (campaign artifacts).
For each issue anchor present in BASE 63279301bc non-test .py and absent on HEAD, the BASE comment/docstring block was re-attached at the HEAD location of the code it explained (matched by the distinctive code line / enclosing def). Sentences already covered by an existing HEAD comment were deduped; the issue number always survives. Insert-only: no code lines changed.
