[datlechin]

Summary

• iCloud saves are conditional (.ifServerRecordUnchanged), so a push built on an older copy of a record is refused.
• Every record is built on the cached server copy and carries only the fields this device changed. A refused save is merged onto the server's copy and sent again; a refusal without that copy fetches it; a record deleted elsewhere goes up again whole, as before.
• Types built fresh with every field (tag, SSH and credential profiles, settings, favorites, table folders, saved queries on iOS) no longer revert fields another device changed.
• The Mac's SSH route is judged against the newer copy by the dial rules: clearing its own route keeps a route another Mac published since. The pull merge uses the same edit.
• A value iOS and the Mac only spell differently is not part of an edit. The iOS mapper and the Mac settings encoder write sorted JSON.
• Settings merge option by option: objects key by key, lists of items with an id item by item. Slash commands two Macs added under one name both stay, the later one as name-2. Shortcuts, AI settings and themes go up whole, since their options depend on each other.
• The record cache holds only what the local copy holds. A merged save keeps the pushed record as base until the local copy takes it, so an edit back to an earlier value still goes up. A category this Mac does not sync is not cached. iOS keeps the base of a copy with a pending edit, applies merged saves right away (a failed write holds the run as an unsaved pull) and settles legacy SSL modes from the pulled record.
• A Mac pull leaves a record with a real pending edit alone; its push merges instead of the pull replacing the edit.
• PushOutcome.merge lets a later save clear an earlier failure.

Test plan

• New: SyncRecordEditTests (package), SyncConflictRebaseTests (macOS), and IOSSyncCoordinatorTests cases for a dirty connection, a saved query and an undo during a merged save, one per case above.
• Changed on purpose: SyncedWriteFailureTests.unsavedSavedQueryHoldsOnlyTheToken now expects an unsaved saved query to stay out of the cache.
• verify.sh: package TableProCore (3668), macOS sync suites (292), iOS sync suites (139), lint.

Needs the maintainer

• A record with no cached base that iCloud already holds (a second Mac turning sync on: settings, slash commands, preset tags) still goes up whole over the iCloud copy. Recommendation: the iCloud copy wins there, as the theme seed already does.
• Shortcuts and AI settings both changed on two Macs keep this Mac's whole category. Merging them per option needs rules for a chord two actions claim and an active provider the other Mac removed. Recommendation: the newer assignment keeps the chord, as the Keyboard settings do, and a missing active provider falls back to the first.

Follows #3769.