Enhance guardian-participant fuzzy matching

During Guardian account creation flow, finding participant with name only doesn't always find the participant: Tried newly created participant account- Kizzy Tester....not found Tried newly created participant email- Kizzy Tester....found Tried existing participant- Aurora Gray....found Tried existing participant- Abigail Grotenhuis...not found Tried existing participant with preferred name- Abby Grotenhuis....not found May be a preferred name issue? —- 🐜 investigation: - we should mirror the fuzzy matching from the type ahead in /people - consider creating a shareable method for this from something that already exists - 🐜 Bug confirmed - ➡️ Cause: Root cause — both the signup check-person endpoint and the post-signup request-participant-link endpoint used the same broken name-matching pattern - ✅ Fix: Use existing fuzzy matcher and name/email matcher used in signup check-person endpoint

During Guardian account creation flow, finding participant with name only doesn't always find the participant: Tried newly created participant account- Kizzy Tester....not found Tried newly created participant email- Kizzy Tester....found Tried existing participant- Aurora Gray....found Tried existing participant- Abigail Grotenhuis...not found Tried existing participant with preferred name- Abby Grotenhuis....not found May be a preferred name issue? —- 🐜 investigation: - we should mirror the fuzzy matching from the type ahead in /people - consider creating a shareable method for this from something that already exists - 🐜 Bug confirmed - ➡️ Cause: Root cause — both the signup check-person endpoint and the post-signup request-participant-link endpoint used the same broken name-matching pattern - ✅ Fix: Use existing fuzzy matcher and name/email matcher used in signup check-person endpoint