Adapt macOS 27 glass and unify Island appearance controls

[Duoasa]

Change

On macOS 27, heavy dark Liquid Glass tints made Island cards look opaque. Keep dark cards translucent using clear native glass with a separate charcoal fill. Add Light / Dark / Auto illustrations for the exposed lower glass, footer controls and floating usage capsule, while retaining the black gradient and dark content cards. The selector appears only for Liquid Glass, defaults to Dark and persists independently of material and capsule visibility.

Unify capsule appearance with this selector and reorganize Island settings into appearance/layout, content, task effects and automatic opening. Use explicit contrasting icon colors in the nonactivating panel; the four toolbar symbols are now 11 pt Semibold within their existing 24 pt buttons. Navigation and provider labels use 12 pt Regular with 12 pt trailing padding on provider tags. The floating capsule, Island shell and settings preview share the same untinted clear material; independent black/white capsule fills are removed while solid accessibility fallbacks remain. The development identity is 0.8.2 Build 9 (internal 73).

Specification

• QV-ISLAND-GLASS-APPEARANCE-001, R1–R5: unified appearance, Accepted / Verifying.
• QV-ISLAND-EXPANDED-GLASS-001: macOS 27 material compatibility.

Verification

• Debug arm64 build and development app startup; source inputs, compiled assets, complete bundle, backup and actual App / Debug dylib / Core load paths verified.
• Three focused tests passed: preference persistence, fixed/automatic appearance and solid accessibility fallback, plus the existing async-question projection assertion. The latter now explicitly unwraps labels to compile with Swift 6.4 while preserving its checks.
• Diff checks passed; no production mock injection.
• Visual acceptance, real system appearance changes, keyboard/VoiceOver and different wallpapers remain with the owner. No automated UI interaction or screenshots were performed.

Source integration only; no public Release or appcast update.