add scrollarea

docs/PLAN.md

@@ -151,6 +151,7 @@ Omarchy `colors.toml` maps almost 1:1: `lighter_background` → `surface`, `dark
 The set stays role-minimal and grows one concept at a time, driven by the unit that needs it. Known planned additions:
 
 - ~~**Overlay scrim + shadow/elevation tokens**~~ — ✅ landed with unit 11 (2026-10-29): `colors.overlay` (translucent-black scrim, denser in dark; TOML-overridable; no platform states one), `Radius.overlay` (10 pt), `Elevations.popover`/`dialog` (transcribed NSPopover-class shadows, builder → `Vec<BoxShadow>`), and `Motion.overlay` (200 ms enter transition). Popover consumes elevation + motion; the scrim waits for Dialog.
+- ~~**Scrollbar thumb token + metrics**~~ — ✅ landed with the ScrollArea unit (2026-10-29): `colors.scrollbar_thumb` (translucent over content: black in light, light gray in dark; TOML-overridable) and `Theme.scrollbar` (`width` 8 pt, `inset` 2 pt, `min_thumb` 24 pt).
 - **`success` / `warning` roles** — with the first severity-bearing component (Toast, badges, validation); the Omarchy mapping above already anticipates them.
 - **`knob` / control-fill role** — only if Slider (unit 7) confirms the Switch's borrowed roles (`primary_foreground` thumb, `border` off-track) as a second consumer; until then no expansion.
 
@@ -208,6 +209,7 @@ Each row is one review unit: build it, show it in the gallery, review, then move
 | 8 | core | Progress | Determinate + indeterminate. |
 | 9 | core | Avatar | Initials; image slot later. |
 | 10 | core | Input (single-line) then multiline, NumberInput | String buffer + `unicode-segmentation` word movement; the field owns its own selection. May seed `crates/editor`. Single-line finishing pass: §6.2. |
+| 11.5 | core | ScrollArea + Scrollbar | ✅ Landed (2026-10-29). Inserted before the remaining overlays — Menus, Lists and Tables all scroll. gpui owns the mechanics (`overflow_*_scroll` + caller-held `ScrollHandle`); the component paints an overlay thumb (`scrollbar_thumb` token, `Scrollbar` metrics) with drag and geometry unit-tested. Wheel input is gpui's; the area stops wheel propagation so nested areas don't co-scroll. Horizontal thumb deferred; auto-hide on idle deferred |
 | 11 | core | Popover | ✅ Landed (2026-10-29). First overlay. Controlled `open` + `on_change` (Rc-shared handler); `trigger`/`content` element closures; panel = surface + `Radius.overlay` + `Elevations.popover` + border, role Dialog with label; `anchored()` + `deferred()` (window-overflow flip for free); enter fade via gpui `with_animation` at `Motion.overlay` (respects reduce-motion); claims keyboard focus while open; escape and click-outside dismiss (outside clicks swallowed). No scrim — native macOS popover model; the overlay token waits for Dialog. Known v1 gaps: no exit animation, trigger aria-expanded left to the app |
 | 11+ | core | Tooltip, Menu, Dialog, AlertDialog, Sheet, Toast | One unit each, same gate. Menu reuses the popover shell + `Radius.overlay`/`Elevations.popover`; Dialog consumes `colors.overlay` (scrim) + `Elevations.dialog` |
 | then | data (new) | List, Table, Tree, Tabs, Sidebar | Created on demand, same gate. |