## Summary
Use native iOS sheets for channel editing and Add Members, with profile
avatars, matching search, and destructive removal dialogs. Canvas
content becomes a tappable preview with Add/Remove actions.
Fix the Settings availability menu and clipped copy confirmation. Align
channel action messages with chat styling and keep agent identities
distinguishable across selection, attribution, and profile surfaces.
### Related issue
No duplicate found in the existing mobile Settings/channel issues and
PRs.
### Testing
- Flutter analysis, formatting, file-size checks, focused collision
regressions, and the full mobile test suite passed.
- Production UIKit picker simulator check passed: distinct
visible/accessibility labels, avatar updates, selected rows, and pubkey
callbacks. Wired into Mobile Swift CI.
- Original UI was built and tested on the physical iPhone with author
confirmation; profile/community data preserved.
- Review fixes await renewed author device confirmation before restoring
`buzz-review-completed` and ready-for-review status.
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Signed-off-by: kenny lopez <klopez4212@gmail.com>
