test(benchmarks): add C#/ASP.NET and TypeScript tasks

Six tasks with hidden checks: ASP.NET validation and 404 handling, C#
cancellation, and TypeScript overlap, deep merge, and debounce fixes, checked
with dotnet run and node --test.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/benchmarks/tasks/18-ts-deep-merge/repo/src/config.ts

@@ -0,0 +1,5 @@
+export type Config = { [key: string]: unknown };
+
+export function mergeConfig(base: Config, override: Config): Config {
+  return { ...base, ...override };
+}