Fix approvals feedback and notifications

[federicodeponte]

Summary

• Upstream DocuSign into the engine-owned BrandLogo/IconSprite pair so cloud does not need a brand-logo overlay fork for shared worker cards.
• On approval rejection with reviewer feedback, queue a normal retry of the same worker with _workeros_review_feedback and retry_of_run_id linking it to the original run.
• Add pending-approval email notifications to configured worker alert recipients with signed review links, using the existing alert throttle store and WORKEROS_EMAIL_FROM sender precedence.

Validation

• python3 -m pytest ../../tests/test_418_approval_gate.py tests/test_approval_decision_toctou_280.py tests/test_l3_run_email_summary.py tests/test_alert_email_throttle.py -q
• npm test -- --run tests/worker-flow-brand-logo.dom.test.tsx
• npm run lint:emdash
• gitleaks detect on the explicit origin/main..HEAD range