docs(16-01): complete multi-user data model foundation plan

- Add 16-01-SUMMARY.md with schema, middleware, and test changes
- Update STATE.md with phase 16 progress and decisions
- Update ROADMAP.md with plan progress (1/4 complete)
- Mark MULTI-01, MULTI-04, MULTI-06 complete in REQUIREMENTS.md

.planning/STATE.md

@@ -2,16 +2,16 @@
 gsd_state_version: 1.0
 milestone: v2.0
 milestone_name: Platform Foundation
-status: planning
+status: executing
 stopped_at: null
-last_updated: "2026-04-03"
-last_activity: 2026-04-03 — v2.0 roadmap created (Phases 14-18)
+last_updated: "2026-04-05"
+last_activity: 2026-04-05 — Completed 16-01-PLAN.md (multi-user data model foundation)
 progress:
   total_phases: 5
   completed_phases: 0
-  total_plans: 0
-  completed_plans: 0
-  percent: 0
+  total_plans: 4
+  completed_plans: 1
+  percent: 5
 ---
 
 # Project State
@@ -21,23 +21,23 @@ progress:
 See: .planning/PROJECT.md (updated 2026-04-03)
 
 **Core value:** Help people make better gear decisions — discover what others use, compare real-world data, and see how a potential buy affects your setup before committing.
-**Current focus:** v2.0 Platform Foundation — Phase 14 (PostgreSQL Migration)
+**Current focus:** v2.0 Platform Foundation — Phase 16 (Multi-User Data Model)
 
 ## Current Position
 
-Phase: 14 of 18 (PostgreSQL Migration)
-Plan: 0 of ? in current phase
-Status: Ready to plan
-Last activity: 2026-04-03 — v2.0 roadmap created (Phases 14-18)
+Phase: 16 of 18 (Multi-User Data Model)
+Plan: 1 of 4 in current phase
+Status: Plan 16-01 complete, executing remaining plans
+Last activity: 2026-04-05 — Completed 16-01 (multi-user data model foundation)
 
-Progress: [----------] 0% (v2.0 milestone)
+Progress: [#---------] 5% (v2.0 milestone)
 
 ## Performance Metrics
 
 **Velocity:**
-- Total plans completed: 0 (v2.0 milestone)
-- Average duration: --
-- Total execution time: --
+- Total plans completed: 1 (v2.0 milestone)
+- Average duration: 8min
+- Total execution time: 8min
 
 *Updated after each plan completion*
 
@@ -45,13 +45,16 @@ Progress: [----------] 0% (v2.0 milestone)
 
 ### Decisions
 
-Key decisions made during v2.0 planning:
+Key decisions made during v2.0 execution:
 - Platform pivot: single-user to multi-user with discovery-first approach
 - External auth provider (self-hosted, open-source) — Logto vs Authentik OPEN decision
 - SQLite to Postgres migration — required by auth provider and multi-user concurrency
 - Structured UGC only — ratings and predefined fields, no freeform text until moderation
 - Separate globalItems table — not a flag on user items table
 - Single-user SQLite mode diverges at v2.0 boundary
+- All API routes require auth (no GET bypass) for per-user data scoping (16-01)
+- OAuth service converted from sync to async for pg compatibility (16-01)
+- getOrCreateUncategorized placed in category.service.ts (16-01)
 
 ### Pending Todos
 
@@ -64,6 +67,6 @@ None active.
 
 ## Session Continuity
 
-Last session: 2026-04-03
-Stopped at: v2.0 roadmap created with 5 phases (14-18) covering 30 requirements
+Last session: 2026-04-05
+Stopped at: Completed 16-01-PLAN.md (multi-user data model foundation)
 Resume file: None