Changed-file tree view

Changes, commit History, and pull-request file lists share a persisted Flat/Tree selector. Tree mode groups safe repository-relative paths into a deterministic depth-first directory hierarchy while preserving each original file object, identifier, and source index.

Selection, include checkboxes, filtering, context menus, and double-click editor actions therefore target the same file in either view. Directory rows are non-selectable and skipped by keyboard navigation. Unsafe, absolute, control-bearing, traversal, overlong, or overdeep paths remain visible as root-level leaves and are never resolved on disk.

The selector and directory accessible names update live in English, playful Hong Kong Cantonese, and compact bilingual mode. A storage failure keeps the current session usable and falls back to Flat on the next start.

Tests cover nested ordering, unsafe-path fallback, selection/source-index preservation, menus/double-click, persistence, and all language modes. See Changed-file trees and diff context for the detailed limits.