Align task sessions with core behavior

[cgasgarth]

Summary

• align dynamic task execution more closely with core task session behavior
• disable todo and primary-only tools in child sessions via the prompt tool map
• track explicit task permission from config so nested task remains off unless explicitly allowed
• add regression tests for task tool selection and explicit task permission detection
• bump package to 0.2.5

Testing

• npm run check
• npm run build