docs(10-02): complete type-branched field rendering and POST handler fix plan

- Create 10-02-SUMMARY.md with decisions, commits, and deviation docs
- Update STATE.md with decisions and metrics
- Update ROADMAP.md phase 10 progress (2/3 summaries)
- Mark FIELD-02 and FIELD-04 requirements complete

.planning/STATE.md

@@ -3,12 +3,12 @@ gsd_state_version: 1.0
 milestone: v1.1
 milestone_name: Smart Document Preparation
 status: unknown
-last_updated: "2026-03-21T18:32:35.250Z"
+last_updated: "2026-03-21T18:51:29.718Z"
 progress:
-  total_phases: 9
+  total_phases: 10
   completed_phases: 9
-  total_plans: 31
-  completed_plans: 31
+  total_plans: 34
+  completed_plans: 33
 ---
 
 # Project State
@@ -47,6 +47,7 @@ Progress: [█████████░░░░] 69% (9/13 phases complete)
 
 *Updated after each plan completion*
 | Phase 09-client-property-address P01 | 25 | 3 tasks | 7 files |
+| Phase 10-expanded-field-types-end-to-end P02 | 2 | 2 tasks | 2 files |
 
 ## Accumulated Context
 
@@ -66,6 +67,8 @@ Recent decisions affecting v1.1 work:
 - [08-02]: Phase 8 ships atomically — 08-01 schema + 08-02 boundary enforcement active simultaneously; no intermediate state where type discriminant exists but filter is absent
 - [Phase 09-client-property-address]: TextFillForm initialData prop pattern: seed rows from Record<string,string> via buildInitialRows helper; pre-seeding done via prop not external controlled state
 - [Phase 09-client-property-address]: Empty string from FormData coerced to NULL via || null before DB write — blank optional fields never store empty string in postgres
+- [Phase 10-expanded-field-types-end-to-end]: date field signing date captured server-side (now hoisted before step 8) — not trusted from client payload
+- [Phase 10-expanded-field-types-end-to-end]: signableFields filter limits POST signaturesWithCoords to client-signature and initials only — eliminates 500 on mixed-field documents
 
 ### Pending Todos