chore(plugins): bulk add package boundary tsconfig rollout

extensions/copilot-proxy/tsconfig.json

@@ -4,5 +4,13 @@
     "rootDir": "."
   },
   "include": ["./*.ts", "./src/**/*.ts"],
-  "exclude": ["./**/*.test.ts", "./dist/**", "./node_modules/**"]
+  "exclude": [
+    "./**/*.test.ts",
+    "./dist/**",
+    "./node_modules/**",
+    "./src/test-support/**",
+    "./src/**/*test-helpers.ts",
+    "./src/**/*test-harness.ts",
+    "./src/**/*test-support.ts"
+  ]
 }