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>

.claude/settings.json

@@ -0,0 +1,31 @@
+{
+  "permissions": {
+    "allow": [
+      "mcp__UnityMCP__read_console",
+      "mcp__UnityMCP__find_gameobjects",
+      "mcp__UnityMCP__find_in_file",
+      "mcp__UnityMCP__get_sha",
+      "mcp__UnityMCP__get_test_job",
+      "mcp__UnityMCP__unity_docs",
+      "mcp__UnityMCP__unity_reflect",
+      "mcp__UnityMCP__validate_script",
+      "mcp__UnityMCP__debug_request_context",
+      "mcp__UnityMCP__manage_script_capabilities",
+      "Bash(git status:*)",
+      "Bash(git diff:*)",
+      "Bash(git log:*)",
+      "Bash(git show:*)",
+      "Bash(git branch:*)",
+      "Bash(git add:*)",
+      "Bash(git commit:*)"
+    ],
+    "deny": [
+      "Bash(rm -rf:*)",
+      "Bash(rm -fr:*)",
+      "Bash(git reset --hard:*)",
+      "Bash(git push --force:*)",
+      "Bash(git push -f:*)",
+      "Bash(git clean -fd:*)"
+    ]
+  }
+}