docs: handoffs for open issues missing dedicated docs

[kuyacarlo]

Summary

• Dedicated Planned handoffs for MVP gaps MVP: Push verdicts to Loki (or configured sink) #77–MVP: A1 regex validation before serve (ReDoS guard) #80
• Thin legacy pointers Presidio PII integration #17 → MVP: Presidio PII gate on /validate #79, Log every verdict to Loki #20 → MVP: Push verdicts to Loki (or configured sink) #77
• Deferred post-MVP handoffs Regulatory change simulator #13, RAG fine-tune & performance test #14, Load test (5s rule) #22
• Does not include MVP: Policy storage schema & versioning #75/MVP: Structured verdict logging schema #76/MVP: Sample policy pack for E2E #81 handoffs (already on PR MVP foundation: fixtures, verdict schema, policy versioning (#81 #76 #75) #86 — leave unmerged per request)

Test plan

• Every previously uncovered open issue has a docs/handoffs/ file with Issue(s): #n
• Index rows readable in docs/handoffs/README.md