Set up DOTS + Netcode for Entities foundation

One-time stack setup per Docs/dots-setup-task.md (Unity 6.4.7 / 6000.4.7f1).
Packages: entities 6.4.0, entities.graphics 6.4.0, netcode 1.13.2, physics 1.4.6.

- Assets/_Project asmdef split: ProjectM.Simulation/Client/Server/Authoring (root ns ProjectM)
- GameBootstrap : ClientServerBootstrap; verified separate client + server worlds in Play Mode
- Gameplay subscene wired into SampleScene as a baking target
- Heartbeat component + Burst ISystem; EditMode smoke test green (1/1)
- In-repo Obsidian vault (Docs/Vault) incl. DR-001 (plain-Entities test over internal NetCodeTestWorld)
- Portable .mcp.json (basic-memory + serena via ${CLAUDE_PROJECT_DIR}); CLAUDE.md conventions
- .gitignore for DOTS baking cache + machine-local config

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

ProjectSettings/ProjectSettings.asset

@@ -923,11 +923,11 @@ PlayerSettings:
   activeInputHandler: 1
   windowsGamepadBackendHint: 0
   enableDirectStorage: 0
-  cloudProjectId: 
+  cloudProjectId: e222f40d-3106-4f0a-843d-c0237ded721b
   framebufferDepthMemorylessMode: 0
   qualitySettingsNames: []
-  projectName: 
-  organizationId: 
+  projectName: Project M
+  organizationId: rain-entertainment-llc
   cloudEnabled: 0
   legacyClampBlendShapeWeights: 0
   hmiLoadingImage: {fileID: 0}