Preserve the correct history limits while editing Favorites

[MiMoHo]

Problem

Two coupled Favorites retention paths can corrupt history state:

1. checkRememberNumPref:forPrimaryStore: always forwards YES, even while editing Favorites. Cancelling a Favorites shrink can therefore overwrite the main rememberNum, leave favoritesRememberNum at the rejected value, and cause later trimming despite the cancellation.
2. checkFavoritesRememberNumPref: always switches to Favorites and restores afterward. If Favorites is already selected in the bezel, that second switch overwrites the stashed reference to the main history; a later save can serialize Favorites as both histories.

Change

• forward the actual isPrimaryStore argument
• return the effective retention limit as declared
• switch to Favorites temporarily only when the main store was active
• restore the main store only after such a temporary switch

Verification

• native regression harness compiles the real AppController with 19 application sources plus a fixture
• first RED: exit 11, favorite limit was forwarded as primary
• second RED after the first fix: exit 15, already-selected favorites store was switched re-entrantly
• final focused test: 1/1 passed, covering primary/favorite forwarding and return values, already-selected Favorites, and temporary switch/restore
• native arm64 link comparison: base and candidate each linked the same 20 PBX sources with 0 errors; no new warning signature and the existing missing-return warning was removed
• Clang analyzer comparison: 13 identical existing diagnostics, 0 errors
• independent pre-commit review of diff SHA-256 0787d5e8d71fc70b527b647b57a38562984226beda0e5e0ead6f84737591c4f1: PASS, no findings
• consolidated-repository integration exposed and reproduced a duplicate-main test-inventory failure; the test now excludes Tests/*.m
• the corrected test passed both in the PR worktree and against the consolidated repository
• independent review of the one-file integration diff SHA-256 9cba2a8440063093aae1f75d0f4733becd7e3966128558f9d8fc00e7de69ad2a: PASS, no findings

Limitation

A full signed Xcode release build and visible UI test were unavailable in this Command Line Tools environment. The native fixture executes the real controller methods and the complete target source-link comparison verifies the app target.