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

docs/ISSUES.md

@@ -103,6 +103,63 @@ Copy this block when adding a new issue:
 
 ---
 
+## #247 — Loot ordering and local dropped-item projection regressed
+
+**Status:** DONE — 2026-07-26; connected loot/drop/selection gate passed
+**Severity:** HIGH
+**Filed:** 2026-07-26
+**Component:** inventory / live-entity projection
+
+**Description:** Double-click loot transferred successfully but settled at an
+unrelated backpack position. Locally dropped items were authoritative and
+visible to retail observers, yet remained invisible in acdream.
+
+**Root cause / status:** The compact container projection sorted a completed
+server move by stale slot state instead of performing retail's separate
+remove-then-`IDList::AddAtNum` insertion. Whole-object drops then exposed two
+projection errors. Inventory-only objects retained canonical CreateObject and
+timestamp state without an App projection sidecar; the Position authority gate
+committed their server position and then rejected the presentation tail
+because it required a pre-existing `LiveEntityRecord`. Accepted Position now
+returns the exact canonical incarnation, and the network presenter crosses
+the normal spatial-hydration boundary before continuing. Objects which already
+retain a sidecar recover whenever `IsSpatiallyProjected` is false.
+`EquippedChildRenderController` also no longer interprets every final `None`
+equip mask as a detach; it requires the actual equipped-to-unequipped edge.
+
+Partial-stack drops have an additional ACE-specific wire omission.
+`HandleActionStackableSplitTo3D` creates a new GUID and sends Position updates,
+but does not send that new object's CreateObject to the initiating session.
+Retail records the source WCID, selected count, and request time for ten
+seconds so the created object can be recognized. acdream now retains that same
+single pending identity; the one matching unknown ACE Position hydrates a
+canonical clone of the source appearance through the normal live-entity path.
+Reconnect evidence proved all prior drops were persisted and received as
+ordinary CreateObjects. Focused ordering, projection, and pending-identity
+tests pass, including stale-authority rejection, first projection construction,
+and no duplicate resource/ready publication.
+
+The follow-up stale marker was a separate projection-lifetime ordering edge.
+Retail keeps canonical selection but suppresses its vivid world marker while
+the object is player-owned or `IN_CONTAINER`. acdream additionally must not
+mistake a retained leave-world `WorldEntity` pose for a current ground pose:
+ACE may publish the drop placement before the new Position. Marker resolution
+now requires both world placement and a current top-level spatial projection.
+The inverse packet order is also safe: a fresh Position remains suppressed by
+ownership until the placement arrives. This uses no timer and does not impose
+camera/PVS visibility, preserving off-screen and through-wall indicators.
+
+**Research:**
+[`research/2026-07-26-retail-inventory-placement-and-world-drop-pseudocode.md`](research/2026-07-26-retail-inventory-placement-and-world-drop-pseudocode.md).
+
+**Acceptance:** Looted items occupy the retail-selected backpack slot in
+server order; locally and remotely dropped items appear once in the world;
+pickup removes the ground marker without clearing inventory selection; re-drop
+shows the marker only at the new authoritative pose. User accepted all four
+connected checks on 2026-07-26.
+
+---
+
 ## #246 — Prepared indoor cells stopped traversing their portals
 
 **Status:** DONE — 2026-07-26; connected house/dungeon gate passed