feat(review): add the changeset review TUI

[lettertwo]

Lands the git-workon-review changeset review TUI

What this adds

git workon review [<source>] opens a TUI for reviewing changesets:

• Any source — auto-detected Graphite stack or uncommitted worktree, plus explicit stack, uncommitted, <ref>, <a..b> / <a...b> ranges, and PR references
• Rendering — side-by-side and inline layouts, collapsed context gaps, word-diff emphasis, tree-sitter highlighting (8 grammars)
• Staging — hunk / file / line-selection stage, unstage, and discard, with an index watcher that picks up external writes
• Navigation — outline pane (flat/tree/stack/stack-tree), continuous file and changeset jumps, fuzzy filter, in-diff search, range-aware copy
• Configuration — git-native workon.review.* config, rebindable per-view keymaps, ? help overlay, base16 theming with auto/dark/light

Verification

• Full workspace green on the merge base: 1434 tests, clippy clean under the newly-bumped 1.97.1 toolchain
• Restacked onto current main (789682a); lockfile conflicts resolved by regenerating rather than hand-merging

This PR exists primarily to run CI on ubuntu-latest — the review crate has only ever been built on macOS, and it carries tree-sitter C grammars, PTY tests, and terminal OSC probes whose Linux behavior is unproven.

Release posture is unchanged: publish = false and dist = false stay set, so this crate stays out of release-plz and cargo-dist.