fix: harden cross-platform release builds

Skip direct POSIX entrypoint execution on Windows CI and prevent test-support modules from entering clean build or npm package output.

tsconfig.build.json

@@ -8,5 +8,5 @@
     "sourceMap": true
   },
   "include": ["src/cli.ts", "src/server/**/*.ts"],
-  "exclude": ["src/**/*.test.ts"]
+  "exclude": ["src/**/*.test.ts", "src/**/*.testSupport.ts"]
 }