- Remove workflow_dispatch and schedule event handling from create-prompt
since agent mode doesn't use the standard prompt generation flow
- Enforce mode compatibility at selection time in the registry instead
of runtime validation in tag mode
- Add explanatory comment in agent mode about why prompt file is needed
- Update tests to reflect simplified event handling
This reduces code duplication and makes the separation between tag mode
(entity-based events) and agent mode (automation events) clearer.