[StanleyLl0yd]

Second screenshot-driven correction for #156.

The apparent 145.8 GB selected Contents vs 187.2 MB "Other (5)" mismatch is not a confirmed size bug: center currently prioritizes the segment under the mouse over keyboard focus and persisted selection. Preserve that contract and make it explicit:

• Label center value as Under pointer / Под указателем, Keyboard focus / Фокус клавиатуры or Selected / Выбрано, with RU/EN catalog entries.
• Resolve source priority deterministically; add regression coverage for pointer > keyboard > selection and empty state.
• Prevent the large default macOS rectangular focus glow via native .focusEffectDisabled() on the already-focusable chart while retaining .focused, arrow keys, Return/Space and clearly accented focused segment outlines.
• Improve separation between nested rings by a slightly stronger brightness/saturation gradient and opaque separators; add palette depth contrast assertion.

Four focused files: SunburstView.swift, Utilities.swift, Localizable.xcstrings, DiskUsageTests/FolderUsageTests.swift.
No filesystem scan/Trash behavior, SwiftUI view-mode restructuring, dependency, version/release, signing or app-icon changes. Original v0.2.0 remains immutable.

Require exact-head macOS Debug XCTest, Release build, Security, Dependency Review, CodeQL Actions/Swift and zero review threads. After merge, verify exact-main. Screen-level visual acceptance on real Mac in RU/EN dark/light, keyboard-only focus, hover and 800×600 remains open in #156.

Updated exact base after #157 squash-merge: 12acbf26ca21dc4558282a589217e302239055d9.
Current synchronized head: ba533877e6dc3947e60aabdaea084bdb5eb41cd9; same four changed files; old standalone base had no overlapping source changes. Full exact-head checks rerun required.