macOS traffic lights misaligned with the titlebar; fixed native position ignores interface zoom

[ElbertePlinio]

Follow-up to #399 / PR #400. The macOS traffic lights were aligned to one static native position while the CSS titlebar scales with interface zoom. AppKit also resets titlebar frames during resize and fullscreen layout, producing permanent drift and a brief snap during fullscreen exit.

Final approach

• Remove static trafficLightPosition from the macOS Tauri config.
• Position the standard AppKit window buttons from a macOS-only Rust module.
• Preserve the native 14pt horizontal inset and center vertically against the zoomed --pf-titlebar-h value.
• Reapply from stable NSWindow notifications for resize, backing changes, and fullscreen lifecycle.
• Leave the fullscreen strip untouched during entry; align on the first windowed update during exit.
• Apply geometry after runtime WebView zoom and persisted-zoom startup.

Progress

• Preserve the superseded PR implementation on backup/pr-403-observer-attempt-20260731
• Reset the feature branch to main and replace the implementation
• Validate startup, resize, and repeated fullscreen transitions at 100%, 125%, and 150%
• Verify fullscreen exit frame-by-frame in a native 60fps capture with no transient snap
• Add Rust, TypeScript, config-drift, and AppleScript coverage
• Run full build, unit, Clippy, Cargo, and local-review validation
• Pass rewritten PR fix(macos): keep traffic lights centered through zoom and fullscreen #403 CI
• User review
• Merge PR fix(macos): keep traffic lights centered through zoom and fullscreen #403

PR: #403

Current status: resolved by merged PR #403.

[ElbertePlinio]

Progress update:

• Rust command + native frame-change observers (close button + titlebar container)
• Fullscreen-transition suppression (animation glitch fixed — recorded)
• Post-resize permanent misalignment fixed (container observer)
• Validation: checks green, live centered at 100/125/150%, resize both directions, fullscreen round-trip
• Review: 1 panel round + 2 fix-verification rounds, P2s fixed
• CI + merge

PR: pending link above
Next: CI, merge. User sanity-check welcome: resize + fullscreen + zoom change on the running dev build.

[ElbertePlinio]

Replacement implementation force-pushed to PR #403.

• Old observer attempt preserved at backup/pr-403-observer-attempt-20260731
• Native 60fps verification shows no fullscreen-exit snap
• Local build, tests, Clippy, full Cargo suite, and final review passed
• CI is now running

Per user request, do not merge; awaiting user review.

[ElbertePlinio]

All six required checks on the rewritten PR are green:

• cargo + tsc + build
• dependency audit
• macOS OMP ACP
• secrets scan
• visual regression
• Windows remote auth

PR #403 remains open and unmerged for user review.

[ElbertePlinio]

Merged PR #403 as a8fb155. All required checks passed. The superseded implementation remains on the local backup branch backup/pr-403-observer-attempt-20260731.