fix(net): sign-extend retail capacity bytes

Mirror PublicWeenieDesc::UnPack MOVSX behavior so ACE's FF capacity sentinels remain -1 instead of becoming 255. This suppresses non-container capacity prose through the normal retail appraisal checks, with raw-wire and formatter regression coverage.

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

docs/ISSUES.md

@@ -110,18 +110,18 @@ crafting, ratings, rare state, and prose. AP-110 records the remaining
 specialized/player-dependent/DAT-name/creature-font/object-preview branches
 explicitly.
 
-The item-format conformance correction then fixed the live Black Phyntos Hive
-counterexample at its source. CreateObject had walked past
-`PublicWeenieDesc.HookItemTypes` and `HookType` without retaining them, so the
-item formatter could not execute retail `ACCWeenieObject::IsHook`. It also
-fell back from a deliberately incomplete appraisal to public Value/Burden and
-printed the hook's 255/255 sentinel capacities as ordinary storage. Hook
-identity now survives the wire/session/object-table path; Value/Burden use
-only the appraisal profile and display `???`/`Unknown` when absent;
-`HasHookedItem` suppresses the hook capacity; lock wording and page-count
-property order match retail; and each report fragment preserves
-`AddItemInfo`'s line/paragraph flag plus LayoutDesc `0x1B`'s white/green/red
-font-color indices.
+The item-format conformance correction first preserved
+`PublicWeenieDesc.HookItemTypes` and `HookType`, stopped falling back from an
+incomplete appraisal to public Value/Burden, and ported hook-profile capacity
+suppression, lock wording, page-count order, `AddItemInfo` paragraph
+boundaries, and the authored white/green/red font list. The connected
+Black Phyntos Hive gate then exposed a separate wire-width error: WCID 28249
+is an NPC-lookalike `Creature`, not a hook, and ACE sends its `-1/-1`
+capacity sentinels as `FF/FF`. Retail `PublicWeenieDesc::UnPack @ 0x005AD470`
+uses `MOVSX` at `0x005AD530` and `0x005AD545`; acdream had zero-extended those
+bytes into `255/255`. CreateObject now sign-extends both capacity bytes, so
+`Appraisal_ShowCapacity`'s existing positive tests naturally suppress the
+sentinels without a name/type workaround.
 
 **Files:** `src/AcDream.Core.Net/Messages/AppraiseInfoParser.cs`;
 `src/AcDream.App/UI/RetailUiRuntime.cs`;

docs/research/2026-07-23-retail-appraisal-ui-pseudocode.md

@@ -363,14 +363,24 @@ IsHook(object):
     return PublicWeenieDesc.HookType != 0
        and PublicWeenieDesc.HookItemTypes != TYPE_UNDEF
 
+UnpackCapacityByte(wireByte):
+    # PublicWeenieDesc::UnPack uses MOVSX at 0x005AD530 and 0x005AD545.
+    # The generated pseudocode's uint8_t temporary is misleading.
+    return sign_extend_int8_to_int32(wireByte)
+
 ShowCapacity(object, profile):
     if object is not a hook or profile does not contain a HookProfile:
         append authored item/container capacity as a new paragraph
         if profile contains PageCount (175) and PageUsed (174):
             append "<used> of <count> pages full." as a new paragraph
 
-    # A hook with a HookProfile describes its mounted item. Its sentinel
-    # 255/255 PublicWeenieDesc capacities are not player-facing capacity.
+    # A hook with a HookProfile describes its mounted item, so the hook's own
+    # capacity is not player-facing capacity.
+
+    # Ordinary creature/NPC-lookalike templates can carry -1/-1 capacity
+    # sentinels. They travel as FF/FF but UnpackCapacityByte restores -1/-1,
+    # so the routine's > 0 tests emit no capacity prose. Black Phyntos Hive
+    # (WCID 28249) is this case: Creature, not Hook.
 
 ShowLock(object, profile):
     if object is a hook:

docs/research/deepdives/r06-items-inventory.md

@@ -411,8 +411,8 @@ if (Behavior & 0x04000000 IncludesSecondHeader):
 
 Per-flag (in exact order):
     0x00000001 PluralName       : WString16L
-    0x00000002 ItemsCapacity    : byte
-    0x00000004 ContainersCapacity: byte
+    0x00000002 ItemsCapacity    : int8, sign-extended to int32
+    0x00000004 ContainersCapacity: int8, sign-extended to int32
     0x00000100 AmmoType         : uint16
     0x00000008 Value            : uint32
     0x00000010 Usable           : uint32 (Usable enum)