fix(interaction): restore retail loot placement and world-drop projection

docs/architecture/retail-divergence-register.md

@@ -108,7 +108,7 @@ accepted-divergence entries (#96, #49, #50).
 
 ---
 
-## 3. Documented approximation (AP) — 90 active rows
+## 3. Documented approximation (AP) — 91 active rows
 
 Wave-0 UI ledger repair (2026-07-10) retired stale AP-38, resolved the AP-84
 collision, restored overwritten paperdoll rows as AP-92/AP-93, and registered
@@ -221,6 +221,7 @@ AP-94..AP-112 for the confirmed retail-UI completion gaps.
 | AP-121 | The `/framerate` command persists acdream's live ShowFps value in the modern `settings.json` Display bag after performing retail's live toggle/notice behavior. The named retail `DoFrameRate` body itself only flips `fShowFramerate` and sends `SetFramerateDisplay`; no equivalent persistence write occurs in that command body. | `src/AcDream.App/Settings/RuntimeSettingsController.cs` (`ToggleFrameRate`) | This preserves acdream's shipped L.0 cross-launch display preference while keeping the live retail mechanism and SmartBox visibility result exact; it changes no gameplay or wire state | A relaunch can retain FPS visibility where the named retail command body alone would not; a future port of retail's wider preference owner must avoid double-persisting or applying conflicting startup state | `ClientCommunicationSystem::DoFrameRate @ 0x005707D0`; `CM_UI::SendNotice_SetFramerateDisplay @ 0x0047A050`; `gmSmartBoxUI::RecvNotice_SetFramerateDisplay @ 0x004D65E0` |
 | AP-122 | The toolbar Use hand is Ghosted when selection is empty. Retail sets state 1 (Normal) and an empty-selection click enters generic `TARGET_MODE_USE`; selected-object enablement and activation remain retail-faithful. | `src/AcDream.App/UI/Layout/ToolbarController.cs` (`RefreshUseButton`) | User explicitly requires no selection to present as unavailable. The disabled retained button consumes the click without opening a cursor; every nonempty selection still uses the exact retail CombatUse/type/ItemUses predicate and the shared activation owner. | Generic pick-then-use mode cannot be entered from the empty toolbar hand; an object must first be selected, after which the same Use command is available. | `gmToolbarUI::HandleSelectionChanged @ 0x004BF380`; `gmToolbarUI::ListenToElementMessage @ 0x004BEE90` |
 | AP-123 | Item cooldowns use the retained toolkit's existing procedural `UiItemSlot` leaf rather than materializing retail's ten `m_elem_Icon_Cooldown_*` child elements. The group lookup, remaining-time formula, exact DAT sprites, step choice, and topmost ReadOrder-8 outcome are faithful. | `src/AcDream.App/UI/Layout/ItemCooldownUiController.cs`; `src/AcDream.App/UI/UiItemSlot.cs` | `UiItemSlot` already consumes/reproduces UIItem children procedurally under the IA-15 retained-toolkit architecture. Selecting one imported sprite at draw time gives every inventory/equipment/shortcut alias the same output without a parallel widget tree or per-cell timers. | A future feature that observes the individual cooldown child visibility/state rather than the rendered UIItem could see no child elements even though the cell looks and advances correctly. | `CEnchantmentRegistry::OnCooldown @ 0x005943C0`; `UIElement_UIItem::UpdateCooldownDisplay @ 0x004E1E20`; common UIItem prototype `0x1000033E` |
+| AP-124 | Local ACE omits the new object's CreateObject to the initiating session after `StackableSplitTo3D`, sending only F748 Position for the previously unknown GUID. acdream retains retail's one pending split source/count/time identity for ten seconds and, only for that otherwise-impossible unknown Position, hydrates a canonical clone of the source description with the new GUID and authoritative world placement. | `src/AcDream.App/World/InventoryWorldDropProjectionController.cs`; `src/AcDream.App/UI/ItemInteractionController.cs`; `src/AcDream.App/Physics/LiveEntityNetworkUpdateController.cs` | Nearby/reconnecting clients receive the ordinary CreateObject, while the initiator otherwise cannot render the authoritative object until relog. A server that sends CreateObject never enters this path; the pending identity is consumed before normal hydration and all other unknown Positions remain rejected. | ACE's F748 does not carry WCID or stack size, so an unrelated unknown Position arriving during the exact pending ten-second window could be associated with the split. Retail confirms WCID/count from CreateObject; removing the approximation requires ACE to send that packet to the initiator. | `ACCWeenieObject::UIAttemptSplitTo3D @ 0x0058D850`; `ACCWeenieObject::DeclareValid @ 0x0058E340`; ACE `Player.HandleActionStackableSplitTo3D` / `TryDropItem`; `docs/research/2026-07-26-retail-inventory-placement-and-world-drop-pseudocode.md` |
 
 ## 4. Temporary stopgap (TS) — 38 active rows + TS-37 historical note (TS-20 retired 2026-07-16 — the later named-retail audit disproved the proposed DrawingBSP polygon filter; TS-37 is a retired-row historical note, not an active count; TS-39 retired R5-V3 — sticky seams bound to the ported PositionManager/StickyManager, radii threaded; TS-45 retired 2026-07-07 — hand-rolled `SphereCollision` replaced by the faithful CSphere family port, fixing the player-vs-monster crowd wedge; TS-3 retired 2026-07-07 — `frames_stationary_fall` accounting ported in the #182 verbatim UpdateObjectInternal rebuild, fixing the airborne falling-animation wedge; TS-41 retired 2026-07-07 — SERVERVEL synth-velocity remote body-drive replaced by the retail interp catch-up + unconditional MovementManager::UseTime, the remote-creature de-overlap #184; TS-42 retired 2026-07-19 — semantic animation completion now precedes the ordered Target/Movement/PartArray/Position tail; TS-44 narrowed again 2026-07-19 — complete orientation joined interpolation, only during-stick enqueue suppression remains)