163b12493b
Per spec FR1 + Phase 1.4 + architecture feedback (data != view): - Data classes DiffHunk, DiffFile -> src/patch_modal.py (alongside PendingPatch; all patch-domain data) - Operations parse_diff/parse_hunk_header/get_line_color/apply_patch_to_file (called by gui_2) -> src/gui_2.py - GUI is a pure view; data lives elsewhere; no new files per AGENTS.md Tests: tests/test_diff_viewer.py imports from src.gui_2 (parse_diff/apply_patch_to_file) and src.patch_modal (DiffFile/DiffHunk).