Use Kong metadata and remove Yearn endorsed monitor

[spalen0]

Summary

• remove the Yearn endorsed monitor from automation, docs, and tests
• replace Yearn yDaemon vault/strategy metadata fetches with Kong GraphQL for the remaining shadow-debt and stuck-trigger monitors
• add Kong fetcher tests

Notes

• monitoring.yaml already did not list the endorsed monitor; removing the scheduled job keeps automation aligned with the existing metadata
• yearn-check-shadow-debt and yearn-check-stuck-triggers remain disabled in automation

Tests

• uv run pytest tests/test_yearn_kong.py tests/test_automation_config.py tests/test_monitoring_config.py
• uv run ruff check protocols/yearn/kong.py protocols/yearn/check_shadow_debt.py protocols/yearn/check_stuck_triggers.py tests/test_yearn_kong.py tests/test_automation_config.py
• uv run ruff format --check protocols/yearn/kong.py protocols/yearn/check_shadow_debt.py protocols/yearn/check_stuck_triggers.py tests/test_yearn_kong.py tests/test_automation_config.py
• uv run python -m py_compile protocols/yearn/kong.py protocols/yearn/check_shadow_debt.py protocols/yearn/check_stuck_triggers.py