T19 Git: diffs unified and split with word marks and folds, three-way merge and conflict resolver, changes list and commit input, commit graph and list, branch selector, branch, tag and stash lists, blame with annotation, file history, pull request card, review thread, diff stat and status badge

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

AGENTS.md

@@ -11,6 +11,7 @@ Ely GPUI Component. A component library for GPUI, in light and dark.
 - Codes: `qrcode` (QR) and `barcoders` (Code 128, EAN-13), both MIT OR Apache-2.0, default features off.
 - macOS extras (tray icon, Dock badge) call AppKit through `cocoa` 0.26 and `objc` 0.2, the crates gpui already links.
 - Terminal: `alacritty_terminal` 0.26 (Apache-2.0, default features off) for the grid, its parser and the pseudo-terminal; `futures` carries its events.
+- Diffs: `similar` 3.2 (Apache-2.0) for line and word diffs and three-way merges; its `unicode` feature splits words at punctuation.
 - Gallery: `examples/gallery`. Website: `frontend/` (Vite 8, pnpm), built after the components.
 
 ## Commands