[Dkm0315]

Part of #326.

Phase 5 of the mobile app: the v3 design across the app, then diff review with keep and undo. Built spec-first: cases MUS-SPEC-23-24A to 24P in docs/spec/clauses/23-mobile.md, each with a red test committed before it went green.

The v3 restyle (24A to 24I)

• Tokens in packages/mobile/src/theme.ts and motion.ts: the v3 dark and light palettes (tonal surfaces, separators inside cells only, 16 % and 26 % tints), the iOS type scale (nothing under 12; prose 17/26; code 13/21, 14 in code blocks), 20 pt text margins and 16 pt card margins, radii 26/24/38, capsule buttons (50 and 36), snappy/gentle/bouncy springs, and a 150 ms crossfade under Reduce Motion.
• Haptics per the v3 table: selection, light, medium, success, warning, and the 320 ms stream tick.
• Glass: iOS 26 Liquid Glass through expo-glass-effect, an expo-blur fallback with the v3 tint and top highlight, and a tonal surface on Android. Scroll-edge fades under the title and above the tab bar.
• Chats: a large title with the computer line, two-line rows in Active and Earlier with 36 pt status glyphs (running ring, amber hand, accent bubble, red triangle, green check, dashed idle ring, clock for queued). No filter chips; search is its own circle beside the glass tab bar.
• Chat: tool steps and thinking fold into one "Worked · N steps" capsule. A live line names the running step, and the streaming reply ends with the accent caret. Send turns into Stop with a moving ring (new chat.stop, act only); with text typed it becomes Steer, with a hint. The composer shows its chips only while focused. A run that finishes while the chat is open resolves into a summary card with Review.
• Approvals lead with their question, then the command well and one line of why. Approve is the one filled action. A watch-only phone is told where to answer.
• Moments: All clear (one success haptic, with receipts of what was just answered), Paired (a shield, who can read the link, Continue), and Run finished.
• Also restyled: Needs you, New chat (task first, grouped Where/Agent/Model, Start at the bottom), Settings (iOS anatomy, an eye for watch-only), the computer switcher, the offline banner, the Projects placeholder, the pair screen (the check code in boxes) and the tablet shell.

Diff review with keep and undo (24J to 24P)

• Desktop, packages/agent-app/src/runtime/mobile/:
  • changes.list: the chat's latest turn, the same one the desktop's changed-files card uses, through review.baselines, review.changes and review.marks. Paths are folder-relative.
  • changes.diff: the desktop's own hunks with their ids, named after the enclosing function, with three lines of context and changed-word ranges. Pages hold 400 lines. Highlighting runs on the desktop with Shiki (JavaScript regex engine, the desktop's dark-plus/light-plus themes, sent as [dark, light] colour pairs), so the phone does no parsing. A new file past the line diff's budget is one whole-file hunk.
  • changes.keep and changes.undo go through review.keep, review.undoHunk and review.undoFile. They are act only, with access checked again right before the write (after a test gate). A stale hash writes nothing, and the path must be one of the turn's changes.
• Phone: the Changes screen has a review ring, files that swipe right to keep and left to undo, and Keep all / Undo all in a glass bar. The diff has one gutter, 13 pt wrapped code, function-named hunk pills, a glass toolbar (previous, next, "1 of 3", Undo, Keep) and swipeable hunks; kept hunks fold into a pill. Widths of 600 pt and up get a split diff. The list is virtualized and asks for the next page near its end. Changes is a glass header button with its count.

Security tests

• A read-only phone's keep and undo are refused, and nothing changes on disk or in the marks.
• A phone revoked while an undo waits at the gate leaves the file as it was.
• A stale hash writes nothing.
• A path outside the turn's changes (README.md, ../../etc/passwd) is refused.
• Read-only chat.stop is refused.

Receipts

• 5,000-line diff (24K), measured locally: 13 pages of at most 400 lines, each page 204 to 257 ms, and the slowest of 130 pings from a second session answered in 6 ms while pages were read.

Device evidence

No phone was attached (adb devices lists nothing), so there are no device screenshots. The restyle is checked in jest only; glass, blur, the shimmer and caret timing, the spring feel and the split diff on rotation are not verified on a device.

Deferred

• The file viewer (item 3): this PR is already past about 2,500 lines.
• The full-width shimmer sweep: it needs a masked view, so the live line brightens and dims instead.
• Large-title collapse into the bar, shared-element transitions, Face ID before Approve (app lock), hinge-aware foldables, and model/access chips in the composer (they need the mid-chat switch).