docs(08-01): complete schema foundation plan — SignatureFieldType discriminant

- Create 08-01-SUMMARY.md with full task documentation and deviation notes
- Update STATE.md: plan 1 of 2 complete, decisions recorded, session updated
- Update ROADMAP.md: phase 8 progress 1/2, 08-01-PLAN.md marked complete

.planning/STATE.md

@@ -2,13 +2,13 @@
 gsd_state_version: 1.0
 milestone: v1.1
 milestone_name: smart-document-preparation
-status: ready-to-plan
+status: in-progress
 last_updated: "2026-03-21"
 progress:
   total_phases: 13
   completed_phases: 7
   total_plans: 43
-  completed_plans: 28
+  completed_plans: 29
 ---
 
 # Project State
@@ -23,9 +23,9 @@ See: .planning/PROJECT.md (updated 2026-03-21)
 ## Current Position
 
 Phase: 8 of 13 (Schema Foundation and Signing Page Safety)
-Plan: 0 of 2 in current phase
-Status: Ready to plan
-Last activity: 2026-03-21 — v1.1 roadmap created (phases 8-13 defined); v1.0 complete (phases 1-7 all shipped)
+Plan: 1 of 2 in current phase (08-01 complete)
+Status: In progress
+Last activity: 2026-03-21 — 08-01 complete: SignatureFieldType discriminant, getFieldType, isClientVisibleField added to schema.ts; Drizzle snapshot 0006 created
 
 Progress: [███████░░░░░░] 54% (7/13 phases complete)
 
@@ -58,6 +58,8 @@ Recent decisions affecting v1.1 work:
 - [v1.1 Research]: Use manual `json_schema` response_format for OpenAI — do NOT use `zodResponseFormat` (broken with Zod v4, confirmed issues #1540, #1602, #1709)
 - [v1.1 Research]: Agent signature stored as base64 PNG TEXT column on users table (2-8KB) — no new file storage needed
 - [v1.1 Research]: Phase 8 must ship atomically (schema discriminant + signing page filter) before any new field type can be placed or sent
+- [08-01]: SignatureFieldType.type is optional on SignatureFieldData — v1.0 JSONB documents have no type; getFieldType() coalesces to 'client-signature'
+- [08-01]: isClientVisibleField() returns false only for 'agent-signature' — all other types including legacy documents are client-visible
 
 ### Pending Todos
 
@@ -71,5 +73,5 @@ None yet.
 ## Session Continuity
 
 Last session: 2026-03-21
-Stopped at: v1.1 roadmap created — ROADMAP.md, STATE.md, and REQUIREMENTS.md traceability updated; ready to plan Phase 8
+Stopped at: Completed 08-01-PLAN.md — SignatureFieldType discriminant, helper exports, and migration snapshot added
 Resume file: None