chore(unity): 固定Unity CLI Loop本地包并移除UnitySkills依赖

Client/Packages/io.github.hatayama.uloopmcp/Editor/Api/McpTools/ExecuteDynamicCode/DESIGN.md

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+# execute-dynamic-code design notes
+
+This directory owns the user-facing `execute-dynamic-code` tool contract.
+The public contract must stay stable even when the internal compiler strategy changes.
+
+## Fast path intent
+
+- The preferred compilation path is Unity-bundled Roslyn.
+- `SharedRoslynCompilerWorkerHost` keeps a warm compiler process so structural cache misses stay fast.
+- The shared worker is an optimization only. It must not own response shaping, security validation, or tool-specific policy.
+
+## Prewarm intent
+
+- Auto prewarm exists to hide first-use compiler startup cost after server startup or recovery.
+- Prewarm must go through the same runtime facade used by normal requests.
+- Prewarm must be single-flight. It should never create a parallel execution lane or bypass runtime idleness checks.
+- Prewarm is allowed to improve latency only. It must not change observable tool behavior.
+
+## Fallback intent
+
+- Preferred order is: shared Roslyn worker -> one-shot Roslyn -> AssemblyBuilder fallback.
+- Fallback changes performance, not semantics.
+- Any fallback from the ideal fast path is a maintainer-visible error condition and must be logged through `DynamicCompilationHealthMonitor`.
+
+## Invariants
+
+- Security validation always runs in Unity after compilation and before execution.
+- In restricted mode, metadata validation and IL validation must both complete before `Assembly.Load`.
+- Tool entry points and use cases depend on runtime-facing facades, not compiler backend details.
+- Worker state is disposable. Domain reload or worker protocol failure must be handled by rebuilding state, not by preserving it.
+- The compile backend may change, but `ExecuteDynamicCodeResponse` shape and user-facing behavior must remain stable.