fix(tests): add and tighten constraint-related tests covering return values, error propagation, concurrency, cooldown timing, and constraint removal

ts_web/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/taskbuffer',
-  version: '5.0.0',
+  version: '5.0.1',
   description: 'A flexible task management library supporting TypeScript, allowing for task buffering, scheduling, and execution with dependency management.'
 }