fix(items): port retail useability and autowear rejection

Use the exact low USEABLE_NO-bit predicate so reset/zero-valued direct-use items such as Blackmoor's Favor reach the ordinary Use request. Port AutoWear's clothing-priority blocker lookup and exact named system notice through the shared activation owner.

Co-authored-by: Codex <codex@openai.com>

docs/research/2026-07-23-retail-item-use-and-autowear-pseudocode.md

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+# Retail item useability and AutoWear rejection
+
+Date: 2026-07-23
+
+## Retail anchors
+
+- `ItemUses::ItemUses @ 0x004FCCB0`
+- `ItemUses::IsUseable @ 0x004FCCC0`
+- `PublicWeenieDesc::Reset @ 0x005ACC70`
+- `PublicWeenieDesc::UnPack @ 0x005AD470`
+- `ItemHolder::DetermineUseResult @ 0x00588460`
+- `ItemHolder::UseObject @ 0x00588A80`
+- `CPlayerSystem::AutoWearIsLegal @ 0x0055EF40`
+- `CPlayerSystem::AutoWear @ 0x005601C0`
+- `ACCWeenieObject::GetObjectAtLocation @ 0x0058CE00`
+
+The named pseudo-C is the behavioral oracle. The matching v11.4186 binary was
+also inspected because an older project note interpreted
+`ItemUses::IsUseable` as a nonzero test. The actual instructions are:
+
+```text
+004fccc0  mov eax,[ecx]
+004fccc2  not eax
+004fccc4  and eax,1
+004fccc7  ret
+```
+
+Therefore the method tests only `USEABLE_NO` (bit zero). A zero-valued
+`ITEM_USEABLE` is usable; `USEABLE_NEVER_WALK` is a movement modifier and does
+not make the object unusable. The literal AutoWear rejection at `0x007CC868`
+is:
+
+```text
+You must remove your %s to wear that
+```
+
+The staged ACE, holtburger, and ACViewer reference directories are currently
+empty in this checkout. Their established roles were still checked: ACE owns
+the authoritative use/wield outcome, while the two client references do not
+replace the retail UI-side legality and notice oracle. No server behavior is
+being inferred or moved client-side here.
+
+## Pseudocode
+
+```text
+ItemUses.IsUseable():
+    return (useableBitfield & USEABLE_NO) == 0
+```
+
+`PublicWeenieDesc::Reset` zeros the useability field. `UnPack` replaces it only
+when the optional useability word is present. Consequently an absent wire word
+and an explicitly packed zero both have retail `USEABLE_UNDEF` value zero and
+both pass `IsUseable`.
+
+```text
+AutoWearIsLegal(itemId, out alreadyWorn, silent):
+    alreadyWorn = false
+
+    if player is not ready for an inventory request:
+        return false
+
+    item = GetWeenieObject(itemId)
+    if item is null:
+        return false
+    if (item.validLocations & 0x08007FFF) == 0:
+        return false
+
+    if (item.priority & playerSystem.clothingPriorityMask) == 0:
+        return true
+
+    player = GetWeenieObject(playerId)
+    if player contains item at a worn location:
+        alreadyWorn = true
+
+    if not silent:
+        if alreadyWorn:
+            display "The <item appropriate name> is already being worn"
+        else:
+            occupied = playerSystem.inventoryMask & item.validLocations
+            blocker = player.GetObjectAtLocation(occupied, item.priority)
+            if blocker exists:
+                display "You must remove your <blocker appropriate name> to wear that"
+
+    return false
+```
+
+```text
+AutoWear(itemId, out alreadyWorn, silent):
+    if not AutoWearIsLegal(itemId, alreadyWorn, silent):
+        return false
+
+    item = GetWeenieObject(itemId)
+    if item exists:
+        item.UIAttemptWield(item.validLocations)
+    return true
+```
+
+## Port boundary
+
+- `ItemUseability.IsUseable` is the one Core implementation of the low-bit
+  rule. Toolbar enablement, item activation, and world interaction consume it.
+- `ItemInteractionController` remains the shared double-click and toolbar-hand
+  path. A zero-valued carried gem such as Blackmoor's Favor therefore emits the
+  ordinary Use request; ACE remains authoritative for its spell and
+  consumption outcome.
+- `AutoWieldController` remains the shared inventory/paperdoll equip owner. It
+  resolves AutoWear blockers from `ClientObjectTable`'s retail-ordered
+  equipment projection and emits the retail literal through system chat.
+- Weapon replacement is unchanged. Retail automatically moves primary weapon,
+  incompatible shield, and incompatible ammunition blockers, while AutoWear
+  rejects overlapping clothing/armor and tells the player what to remove.