fix(ui): complete retail inventory scroll polish

Preserve pixel scroll offsets across inventory rebuilds, crop partially visible rows with nested geometry/UV clips, and replace the obsolete 560px resize ceiling with available screen height. Keep retail's row-sized wheel step while allowing continuous scrollbar thumb positions.

Co-Authored-By: Codex <codex@openai.com>

docs/architecture/retail-divergence-register.md

@@ -160,7 +160,7 @@ AP-94..AP-110 for the confirmed retail-UI completion gaps.
 | AP-51 | Main-pack `m_topContainer` cell (element `0x100001C9`) draws the constant backpack icon via a hardcoded base-icon literal `0x0600127E` + `ItemType.Container` (composited over the Container type-underlay), rather than resolving it at runtime the way retail does. Sprite VISUALLY CONFIRMED (2026-06-22 live gate). | `src/AcDream.App/UI/Layout/InventoryController.cs` (`Populate`, main-pack cell) | Retail's `IconData::RenderIcons` IsThePlayer branch draws a CONSTANT backpack with `m_itemType = TYPE_CONTAINER` (the original AP-51 "equipped-pack weenie icon" premise was wrong). The exact runtime resolution is unconfirmed: a research dat-dump misreported `GetDIDByEnum(0x10000004,7)` as the green tile `0x060011F4` (which rendered green-no-pack at the gate); the real backpack `0x0600127E` was identified by dat export + user confirmation. We pin the visually-verified literal (cf. AP-55). Retire when the runtime resolve is reproduced + confirmed. | If the pinned sprite diverges from what retail resolves at runtime, the main-pack icon goes stale. | `IconData::RenderIcons` IsThePlayer branch 0x0058d1ee (decomp 407546-407549); sprite `0x0600127E` dat-exported + visually confirmed |
 | AP-52 | Side-bag column slot count defaults to 7 (the dat column height) when the player's `ContainersCapacity` is absent/0. | `src/AcDream.App/UI/Layout/InventoryController.cs` (`Populate`) | `ContainersCapacity` is not reliably on the player ClientObject yet; 7 is the standard side-pack cap + the dat column (`0x100001CA`, 36×252) holds exactly 7. | An 8th-pack (Shadow of the Seventh Mule aug) character shows one too few side-bag slots — cosmetic. | retail gmBackpackUI side-pack column; ACE `ContainersCapacity` |
 | AP-53 | Contents grid slot count defaults to 102 (main pack) or 24 (side bag) when the open container's `ItemsCapacity` is absent/0. Container-switching is now wired (D.2b): clicking a side bag sends `Use 0x0036` and the grid repopulates from `ViewContents 0x0196`. This row covers only the capacity *default* when the server omits `ItemsCapacity`. | `src/AcDream.App/UI/Layout/InventoryController.cs` (`Populate`) | `ItemsCapacity` is not reliably on every ClientObject yet; 102/24 are the retail standard capacities. Retire when `ItemsCapacity` is confirmed delivered for all containers. | A non-102/24 pack shows the wrong empty-slot count — cosmetic only. | retail main-pack capacity 102; side-pack 24; ACE `ItemsCapacity`; `ViewContents 0x0196` |
-| AP-54 | Inventory window vertical resize is a toolkit approximation: bottom-edge drag, expand-only (Min = dat default 372 px, Max = 560 px constant), contents grid/sub-window/scrollbar/backdrop stretched via overridden `Left\|Top\|Bottom` anchors. | `src/AcDream.App/Rendering/GameWindow.cs` (inventory frame setup) | retail's gmInventoryUI resize lives in keystone.dll (no decomp); the anchor-stretch + 372..560 range matches the observed retail behavior for the dev loop. | The expand range / which elements reflow could differ from retail (e.g. retail may allow shrink-below-default); shrink is intentionally disabled for now. | retail gmInventoryUI resize (keystone.dll, no decomp); `UiNineSlicePanel` resize |
+| AP-54 | Inventory window vertical resize is a toolkit approximation: bottom-edge drag, expand-only (Min = dat default 372 px, Max = available screen height), contents grid/sub-window/scrollbar/backdrop stretched via overridden `Left\|Top\|Bottom` anchors. | `src/AcDream.App/UI/RetailUiRuntime.cs` (inventory frame setup) | retail's gmInventoryUI resize lives in keystone.dll (no decomp); using the screen rather than the former arbitrary 560 px cap keeps the full vertical resize usable at every persisted size. | Which elements reflow or whether retail permits shrink-below-default could differ; shrink below the authored default remains disabled. | retail gmInventoryUI resize (keystone.dll, no decomp); `UiNineSlicePanel` resize |
 | AP-55 | The toolbar's item slots keep the hardcoded `UiItemSlot.EmptySprite = 0x060074CF` rather than resolving their cell template via attribute `0x1000000e`. Correct in outcome (the toolbar's `0x1000000e` resolves to a generic prototype whose empty media is `0x060074CF`) but not dat-resolved. | `src/AcDream.App/UI/UiItemSlot.cs` (`EmptySprite` default); `src/AcDream.App/UI/Layout/ToolbarController.cs` | The inventory lists now port the retail resolver (`ItemListCellTemplate`); the toolbar was left on its hardcoded default to avoid regressing frozen, working art. Retire when the toolbar is routed through `ItemListCellTemplate`. | If a future toolbar layout's `0x1000000e` points at a non-generic prototype, the toolbar would show stale art. | `UIElement_ItemList::InternalCreateItem` 0x004e3570; catalog `0x21000037` |
 | AP-57 | The open-container triangle (`0x06005D9C`) + selected-item square (`0x06004D21`) are drawn as **procedural `UiItemSlot` overlays** keyed by `_openContainer` plus Core `SelectionState.SelectedObjectId`, reproducing the retail keying (`item.itemID == openContainerId / selectedID` per `UpdateOpenContainerIndicator 0x004e3070` / `SetSelectedObject 0x0058c2e0`) but not via the dat prototype's `m_elem_Icon_OpenContainer`/`m_elem_Icon_Selected` state elements + `SetOpenContainerState`/`SetSelectedState` calls. | `src/AcDream.App/UI/UiItemSlot.cs`; `src/AcDream.App/UI/Layout/InventoryController.cs` | The procedural overlay produces the correct visual result; the 36×36 container prototype (`0x1000033F`) lacks the square child, so the procedural overlay is the only way to show the square on a selected bag — the dat-state path retail uses would require the prototype to be richer than it is. | A cell that should show an indicator via a dat-state path retail uses but we don't would be missed; outcome currently matches retail for the open/selected indicator cases. | `UIElement_ItemList::UpdateOpenContainerIndicator` 0x004e3070; `ACCWeenieObject::SetSelectedObject` 0x0058c2e0; `SetOpenContainerState` 0x004e1200; `SetSelectedState` 0x004e1240 |
 | AP-59 | The per-cell container **capacity bar** (retail `UIElement_UIItem::UpdateCapacityDisplay 0x004e16e0`, element `0x10000347`) is drawn as a **procedural `UiItemSlot` overlay** (track `0x06004D22` full + fill `0x06004D23` clipped bottom-up to `GetContents(guid).Count / ItemsCapacity`), not via a real dat `UIElement_Meter` child. **Right-anchored flush** (the dat rect X=26 in a 36px cell sat ~5px off the edge — flush per the visual gate) and **bottom-up fill assumed** (the dat `m_eDirection` 0x6f isn't read, cf. AP-50). A CLOSED side bag reads empty until opened (its contents aren't indexed until `ViewContents`) — faithful to retail's known-children count, divergent if retail pre-loads. | `src/AcDream.App/UI/UiItemSlot.cs` (`CapacityFill` draw); `src/AcDream.App/UI/Layout/InventoryController.cs` (`SetCapacityBar`) | UiItemSlot is a behavioral leaf that paints overlays procedurally (cf. AP-57); the meter sprites + fill formula are the faithful port. Right-anchor + bottom-up were visual-gate calls. Further visual polish is deferred — ISSUES #146. | Fill direction / exact bar rect could differ from retail's `m_eDirection` + dat X; closed-bag bars read empty if retail pre-loads container counts. | `UIElement_UIItem::UpdateCapacityDisplay` 0x004e16e0; element `0x10000347` (back `0x06004D22` / front `0x06004D23`); `GetNumContainedItems` |