Match macOS scan menu titles to action tiles

[enaboapps]

Mac scan menu titles appeared in a black rectangular prompt with small offset text. Menu titles now use a tile-aligned #1E232E background with 10-point rounded corners and centred 18-point white semibold text, scaled with the menu. Native title views are reused and unchanged frames are skipped.

The renderer passes an internal menu-title presentation hint. Other prompts and Windows retain their existing rendering. Native layers draw the rounded background without bitmap scaling; the existing QuartzCore dependency now enables its layer colour and radius bindings. No settings or protocol changes.

Validation:

• npm lint, 147 frontend tests plus 5 update-feed tests, and production build passed.
• cargo fmt, clippy, 353 Rust unit tests plus 7 configuration tests passed.
• Independent review of 61f6e03 found no actionable issues.
• Built and inspected in the Mac VM: main menu, More, Scanning, two-column Scroll title, Back to rows and Select to resume. Text remains centred, title width follows the tile grid, and TextEdit retains foreground focus through menu navigation. Small-screen and scaled geometry covered by automated tests.
• Original VM settings restored and verified; VM returned to its prior suspended state. Signed host Mac app untouched.
• All CI checks passed, including macOS and Windows packaging, dependency audit and CodeQL. The frontend job passed on retry after an initial existing pairing-dialog timeout; the targeted local retest also passed.

Closes #761