feat(ui): port retail selected-stack quantity

Bind the authored stack count entry and horizontal slider to one Core split-quantity owner, preserve retail count-first naming and exact 1000-step rounding, refresh on stack changes, and consume the selected amount during merges. Conformance covers the production DAT fixture and retained pointer/focus paths.

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

docs/plans/2026-04-11-roadmap.md

@@ -490,10 +490,11 @@ behavior. Estimated 17–26 days focused work, 3–5 weeks calendar.
 - **✓ SHIPPED — Wave 4.3a shortcut-alias boundary.** Drag feedback now preserves retail's neutral/accept/reject distinction. Inventory and paperdoll apply the `(DropItemFlags & 0xE) == 0` physical-item gate, so a toolbar alias can reorder within the toolbar but can never move, unwield, wield, or drop the object it references. Live equipped-helmet gate passed 2026-07-11: inventory drop removed only the shortcut.
 - **✓ SHIPPED — Wave 4.3b source-aware toolbar transactions.** Pure Core `ShortcutDropPlanner` ports `gmToolbarUI::HandleDropRelease @ 0x004BE7C0`: fresh inventory drops displace cyclically right (with wrap), shortcut aliases restore to their vacated source, duplicate objects are removed before placement, full bars intentionally lose the displaced entry when retail finds no empty slot, and every transaction is planned before local mutation then emitted in exact Remove/Add order. Full-stack rekey planning preserves the raw spell word. AP-102 retired; 4,646 automated tests pass; live inventory-to-occupied displacement and toolbar reorder gate passed 2026-07-11.
 - **✓ SHIPPED — Wave 4.3c remaining drop branches + stack merge.** `UiButton` now has a reusable retained item-drop-target seam; gmToolbarUI's inventory/backpack button accepts only fresh physical items, draws the exact authored green-arrow overlay `0x060011F7`, and sends them to the player container while shortcut aliases remain neutral. Pure Core `StackMergePlanner` ports `IsMergeAttemptLegal @ 0x00586F30` and `AttemptMerge @ 0x005878F0`; inventory drops try legal same-WCID stack merges before normal insertion, clamp `0x0054` amount to destination capacity, immediately broadcast retail's misleadingly named `FullMergingItem` notice to rekey the toolbar, and select the destination. Existing destination shortcuts are removed before rekey. Warning-free Release build and 4,660 tests pass; live stack-merge gate passed 2026-07-11. Backpack-button drop gate remains pending.
+- **✓ IMPLEMENTED — Wave 4.4a selected-stack controls.** `SelectedObjectController` now formats retail's count-first stack name, reveals the authored numeric entry and horizontal DAT slider, initializes both to the full stack, refreshes them on selected-object stack changes, and shares one Core split quantity with inventory merge. Exact cdb-pinned 1000-step slider rounding, entry clamping, real-DAT fixture media, and pointer drag have conformance tests. Warning-free App Release build and 4,683 tests pass; live visual gate pending 2026-07-11. Selected-item mana and remaining toolbar buttons stay under AP-101.
 - **✓ SHIPPED — Character window** (`LayoutDesc 0x2100002E`, `CharacterStatController`, 2026-06-26, same branch). **Visually user-confirmed 2026-06-26 — Attributes tab reads as retail.** Three tabs, header (name/heritage/PK), large-gold level number (dat font, `largeDatFont` 18px), "Total Experience (XP):" + "XP for next level:" captions, 9-row attribute list (icons + right-aligned values + Health/Stamina/Mana vitals), click-to-select (top/bottom selection bars + footer State-B "{Attr}: {value}" / "Experience To Raise: Infinity!" + affordability-gated raise triangles), centered footer. User noted "still needs some polish for later" — deferred to Issue #158.
 - **✓ SHIPPED — D.5.4 — Client object/item data model (foundation).** Shipped 2026-06-18 (`b506f53`..`a33e897`, 11 commits). Renamed `ItemRepository`→`ClientObjectTable` / `ItemInstance`→`ClientObject`; broadened the table to hold EVERY server object (retail `weenie_object_table` shape). `CreateObject` is now the canonical merge-upsert (`ClientObjectTable.Ingest`, retail `SetWeenieDesc` semantics) via a new Core.Net `ObjectTableWiring` (off GameWindow); `DeleteObject` evicts; `PlayerDescription` is a membership manifest (`RecordMembership`); live container-membership index (`GetContents`, retail `object_inventory_table`). `_liveEntityInfoByGuid` retired (selection/describe resolve from the one table). Root fix: the old enrich-existing-only `EnrichItem` dropped `CreateObject`s for items with no `PlayerDescription` stub — live-Coldeve 4/6 hotbar slots blank; items are now created, not dropped. **Crux resolved:** retail is TWO tables (`object_table` + `weenie_object_table`), NOT one — acdream's `WorldEntity` (3D system) + `ClientObjectTable` (data/UI) split was already architecturally faithful; the fix was the ingestion path, not a table unification. 2671 tests green.
 - **Roadmap correction (2026-07-10):** the completion order is now the architecture-first campaign in `docs/superpowers/plans/2026-07-10-retail-ui-fidelity-completion.md`. Retail `gmToolbarUI` is object-only: preserve `ShortCutData.index_`, `objectID_`, and `spellID_`, but do not invent spell glyphs on this bar. `PlayerModule::favorite_spells_[8]` feeds separate spell bars.
-- **☐ D.5.3 — Toolbar selected-object display (issue #141).** Wire unified selection to the hidden mana meter (`0x100001A2`), stack entry (`0x100001A3`), stack slider (`0x100001A4`), and complete health/name behavior. Exact raw `ShortCutData` preservation is already shipped in Wave 4.2; the eight `favorite_spells_` lists belong to the separate spellbook/spell-bar phase. (Click-to-use + peace/war + health/name already landed.)
+- **☐ D.5.3 — Toolbar selected-object display (issue #141).** Wire unified selection to the hidden mana meter (`0x100001A2`) and complete residual health policy. Stack entry (`0x100001A3`), stack slider (`0x100001A4`), formatted count/name, shared split quantity, click-to-use, peace/war, and health/name are implemented. Exact raw `ShortCutData` preservation is already shipped in Wave 4.2; the eight `favorite_spells_` lists belong to the separate spellbook/spell-bar phase.
 - **☐ D.5.5+ — Core panels.** Inventory (`gmInventoryUI`/`gmBackpackUI`), equipment/paperdoll (`gmPaperDollUI`/`gm3DItemsUI` + the `UiViewport` 3D doll), vendor, trade, spellbook. Research drop done (`docs/research/2026-06-16-*`). Depends on **D.5.4** (data model) + the item-slot/list/icon spine (D.5.1/D.5.2) + the **window manager** (Plan 2: open/close/z-order/persist + faithful grip/dragbar drag-resize) + the drag-drop spine wired (`UiRoot` has the chain; the per-cell accept/drop hooks are still stubs in `UiField`). Also deferred from D.5.1: drag/reorder + the `AddShortcut`/`RemoveShortcut` mutate wire.
 - **D.6 — HUD.** **Radar/compass IMPLEMENTED 2026-07-10; live-world visual gate pending.** It is the retained retail `gmRadarUI` (`LayoutDesc 0x21000074`): a 120×140 circular radar (`0x06004CC1`) with N/E/S/W token sprites orbiting the face, a fixed bright-green player marker, and the coordinate footer (`0x06004CC0`). Projection is `radarPixelRadius / radarRange` with 75 m outdoor / 25 m indoor ranges — there is no 1.18 factor or scrolling compass strip. It lives in `AcDream.App/UI` beside the other imported retail panels. Remaining D.6: target name plate, damage floaters, and other world-space HUD elements through the raw `TextRenderer` path. See slice 06 §A.2, `docs/research/2026-07-10-retail-radar-pseudocode.md`, and the named `gmRadarUI` decomp.
 - **✓ SHIPPED — D.7 — Cursor manager (user-confirmed 2026-07-11).** All reachable `ClientUISystem::UpdateCursorState @ 0x00564630` branches resolve through production DAT EnumIDMap table 6, with event-ordered global-default versus captured/hovered `MediaDescCursor` layering from `UIElementManager::CheckCursor @ 0x0045ABF0`. OS fallback remains only AP-72 and emits a visible diagnostic. The live gate covered world/object, combat, targeted-use, text, move/resize, and drag contexts; combat-indicator mouse clicks and the quick key share the same toggle command.