Sync paint strokes across the network via command replication

Replicate brush strokes as self-contained commands instead of texture
pixels: the owner emits each committed stamp (local placement plus brush
state, byte-quantized) and remotes replay it through the same draw path,
reproducing identical maps without streaming megabytes.

- MeshPainter.Net.cs: PaintStampNet serializable stamp, OnStampCommitted
  owner-capture event (no-op without listener), ApplyNetworkStamp remote
  replay, seedable spray for deterministic speckle.
- MeshPainter.cs: emit stamp after drawing, seed spray only when synced.
- PlayerPaintSync.cs: NetworkBehaviour batching owner stamps reliably
  (ServerRpc -> ClientRpc) with echo guard; remote disables local painting.
- Player/Hider/Hunter prefabs: PlayerPaintSync plus NGO GlobalObjectIdHash.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Assets/Prefabs/Hider.prefab

@@ -12,13 +12,17 @@ PrefabInstance:
       propertyPath: scale
       value: 0.5
       objectReference: {fileID: 0}
+    - target: {fileID: 1557561356852236266, guid: 97017ed3bb40aff4e885440d9a7336ee, type: 3}
+      propertyPath: GlobalObjectIdHash
+      value: 708302045
+      objectReference: {fileID: 0}
     - target: {fileID: 4587432968399885263, guid: 97017ed3bb40aff4e885440d9a7336ee, type: 3}
       propertyPath: m_Enabled
       value: 1
       objectReference: {fileID: 0}
     - target: {fileID: 5384024074013944205, guid: 97017ed3bb40aff4e885440d9a7336ee, type: 3}
       propertyPath: m_Name
-      value: Player Variant
+      value: Hider
       objectReference: {fileID: 0}
     - target: {fileID: 6997860362608943113, guid: 97017ed3bb40aff4e885440d9a7336ee, type: 3}
       propertyPath: m_LocalScale.x

Assets/Prefabs/Hunter.prefab

@@ -16,6 +16,10 @@ PrefabInstance:
       propertyPath: sprintSpeedMultiplier
       value: 2
       objectReference: {fileID: 0}
+    - target: {fileID: 1557561356852236266, guid: 97017ed3bb40aff4e885440d9a7336ee, type: 3}
+      propertyPath: GlobalObjectIdHash
+      value: 1884035523
+      objectReference: {fileID: 0}
     - target: {fileID: 5384024074013944205, guid: 97017ed3bb40aff4e885440d9a7336ee, type: 3}
       propertyPath: m_Name
       value: Hunter

Assets/Prefabs/Player.prefab

@@ -49,6 +49,7 @@ GameObject:
   - component: {fileID: 6847253018511389861}
   - component: {fileID: 8574096554986372233}
   - component: {fileID: 8646586982149381366}
+  - component: {fileID: 4234684093581208771}
   m_Layer: 0
   m_Name: Player
   m_TagString: Player
@@ -111,7 +112,7 @@ MonoBehaviour:
   m_Script: {fileID: 11500000, guid: 463b6be548abf464287096e1e92fcd01, type: 3}
   m_Name: 
   m_EditorClassIdentifier: Assembly-CSharp::PlayerCharacterController
-  persistPlayer: 1
+  persistPlayer: 0
   playerSaveId: 
   moveSpeed: 2
   sprintSpeedMultiplier: 3.2
@@ -224,7 +225,7 @@ MonoBehaviour:
   m_Script: {fileID: 11500000, guid: d5a57f767e5e46a458fc5d3c628d0cbb, type: 3}
   m_Name: 
   m_EditorClassIdentifier: Unity.Netcode.Runtime::Unity.Netcode.NetworkObject
-  GlobalObjectIdHash: 0
+  GlobalObjectIdHash: 1963377418
   InScenePlacedSourceGlobalObjectIdHash: 0
   DeferredDespawnTick: 0
   Ownership: 1
@@ -310,6 +311,20 @@ MonoBehaviour:
   m_Name: 
   m_EditorClassIdentifier: Assembly-CSharp::PlayerAnimationSync
   ShowTopMostFoldoutHeaderGroup: 1
+--- !u!114 &4234684093581208771
+MonoBehaviour:
+  m_ObjectHideFlags: 0
+  m_CorrespondingSourceObject: {fileID: 0}
+  m_PrefabInstance: {fileID: 0}
+  m_PrefabAsset: {fileID: 0}
+  m_GameObject: {fileID: 5384024074013944205}
+  m_Enabled: 1
+  m_EditorHideFlags: 0
+  m_Script: {fileID: 11500000, guid: f1b1a094f669d6b458370f63773462ed, type: 3}
+  m_Name: 
+  m_EditorClassIdentifier: Assembly-CSharp::PlayerPaintSync
+  ShowTopMostFoldoutHeaderGroup: 1
+  maxStampsPerFrame: 64
 --- !u!1 &6840099669803454162
 GameObject:
   m_ObjectHideFlags: 0
@@ -437,7 +452,7 @@ MonoBehaviour:
   brushShader: {fileID: 0}
   dilateShader: {fileID: 0}
   packMsShader: {fileID: 0}
-  persistPaint: 1
+  persistPaint: 0
   saveId: 
   pipette: 0
   spray: 0