feat: add CALL-E Goal Run tools

[Derekwang2002]

Summary

• Add Dify tools to list and read published Goals.
• Add safe Goal Run creation, reads, and polling for a persisted result or final error.
• Validate E.164 recipients, flat scalar variables, and required business-stable idempotency keys.
• Update the plugin's API reference to the supplied v1 documentation endpoint.

Impact

Existing Call tools remain compatible. Goal Run tools default to previews and require both dry_run=false and confirm_live_call=true before a phone call can start.

Validation

• pytest -q (25 passed)
• python -m compileall provider tools utils main.py
• dify plugin package ./api-v06-goal-runs