v0.4.1

Description:

Removed const RETRY_POLICY and DELAY_SECONDS from Task trait.
Added retry_policy() and delay_seconds() methods with defaults (exponential backoff, 3 retries; 3 seconds).
Updated new_meta to use instance-specific values via these methods.
Enables tasks to set custom retry policies and delays per instance.
Changes:

Task trait: Removed constants, added methods.
MyTask: Added fields retry_policy and delay_seconds, implemented new methods.
No breaking changes; defaults preserve existing behavior.