Move the ServerShared data model onto CultLib's CultCache

Cut 8b. Aetheria.Shared builds headless against GameCult.Caching and
GameCult.Caching.MessagePack at the pinned CultLib; the pin guard also
checks the Caching project exists.

Documents: [CultDocument("aetheria.<type>", "1")] with [MessagePackObject]
and integer [Key]s on the Q7 concrete types (the eight ItemData leaves,
Faction, FactionProductData, PersonalityAttribute, NameFile, OrbitData, the
four BodyData leaves, SavedZone, SavedGame, PlayerSettings, InputLayout).
SavedGame and PlayerSettings are [CultGlobal]; Name members are [CultName].
ItemData, CraftedItemData, EquippableItemData, BodyData and AgentTask lose
[MessagePackObject]; BodyData and AgentTask lose their [Union]s. InputLayout
moves into ServerShared so AetheriaStores can route it.

References: Guid and DatabaseLink<T> members become CultRecordRef<T>;
Guid-keyed maps become ref-keyed with [CultReference(..., many: true)];
ZonePack holds refs to orbit and body records. Runtime maps (Zone orbits,
bodies and belts, cargo ItemsOfType, agent targets) key by CultRecordKey.
Identity is the record key: ID comparisons become reference or key
comparisons. StatModifierData.RequireBehavior is a simple type name.

AetheriaStores.Open composes the catalog (read-only unless writable), run
and player stores, one home per type. CultRecordRefs carries IsSet, a
null-safe Get(ref), RefOf (key from TryGetHandle) and Upsert.
ItemManager.GetData is the one item resolution path. MathResolver is
declared by [assembly: CultCacheFormatterResolver].

Inspector attributes: text, range and asset path map onto CultLib's
CultInspector attributes (asset path only on string members); every
replaced Aetheria attribute keeps [Inspectable] for the runtime panel.

Builds: Aetheria.Shared. Does not build: AetherDb and the Unity project,
which follow.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Assets/Scripts/ServerShared/PlayerSettings.cs

@@ -1,9 +1,10 @@
+using GameCult.Caching;
 using System;
 using System.Collections.Generic;
 using System.Globalization;
 using MessagePack;
 
-[MessagePackObject]
+[CultDocument("aetheria.playersettings", "1"), CultGlobal, MessagePackObject]
 public class PlayerSettings
 {
     [Key(0)] public string Name = "Anonymous";