docs(01-02): complete body-size-limits and test-hardening plan

- 01-02-SUMMARY.md: plan completion summary with deviations
- STATE.md: advanced plan position, added decisions, updated metrics
- ROADMAP.md: phase 01 marked complete (2/2 plans)
- REQUIREMENTS.md: DATA-03 and DATA-04 marked complete

.planning/ROADMAP.md

@@ -32,7 +32,7 @@ Decimal phases appear between their surrounding integers in numeric order.
 
 Plans:
 - [x] 01-01-PLAN.md — Fix INSERT OR REPLACE → UPSERT in UpdateEvent(); enable PRAGMA foreign_keys = ON in InitDB(); add regression test
-- [ ] 01-02-PLAN.md — Add http.MaxBytesReader body limits to 3 handlers (413 on oversized); replace 6 silent test returns with t.Fatalf
+- [x] 01-02-PLAN.md — Add http.MaxBytesReader body limits to 3 handlers (413 on oversized); replace 6 silent test returns with t.Fatalf
 
 ### Phase 2: Backend Refactor
 **Goal**: The codebase has a clean Store interface and Server struct so the SQLite implementation can be swapped without touching HTTP handlers, enabling parallel test execution and PostgreSQL support