feat: remove workspace file count limit, raise total size to 4MB

- maxWorkspaceFiles: 16 → Number.MAX_SAFE_INTEGER (unlimited)
- maxWorkspaceFilesTotalBytes: 512KB → 4MB
- Enables large skill directories (e.g. arm2d-skill with references)

src/common/validation.ts

@@ -164,9 +164,9 @@ function validateResourceSkillRefs(value: unknown): NonNullable<ResourceBundleRe
   });
 }
 
-const maxWorkspaceFiles = 16;
+const maxWorkspaceFiles = Number.MAX_SAFE_INTEGER;
 const maxWorkspaceFileBytes = 128 * 1024;
-const maxWorkspaceFilesTotalBytes = 512 * 1024;
+const maxWorkspaceFilesTotalBytes = 4 * 1024 * 1024;
 
 function validateResourceWorkspaceFiles(value: unknown): NonNullable<ResourceBundleRef["workspaceFiles"]> {
   if (!Array.isArray(value)) throw new AgentRunError("schema-invalid", "resourceBundleRef.workspaceFiles must be an array", { httpStatus: 400 });