docs(02-01): complete two-layer memory plan — SUMMARY, STATE, ROADMAP, REQUIREMENTS

- SUMMARY.md: memory system docs (Redis sliding window + pgvector HNSW)
- STATE.md: 67% progress (6/9 plans), 3 key decisions, metrics logged
- ROADMAP.md: Phase 2 plan progress updated (2 summaries complete)
- REQUIREMENTS.md: AGNT-02 (conversational memory), AGNT-03 (cross-session recall) marked complete

.planning/STATE.md

@@ -3,14 +3,14 @@ gsd_state_version: 1.0
 milestone: v1.0
 milestone_name: milestone
 status: planning
-stopped_at: Completed 02-agent-features/02-03-PLAN.md
-last_updated: "2026-03-23T20:44:35.519Z"
+stopped_at: Completed 02-agent-features/02-01-PLAN.md
+last_updated: "2026-03-23T20:46:53.813Z"
 last_activity: 2026-03-23 — Roadmap created, ready for Phase 1 planning
 progress:
   total_phases: 3
   completed_phases: 1
   total_plans: 9
-  completed_plans: 5
+  completed_plans: 6
   percent: 0
 ---
 
@@ -55,6 +55,7 @@ Progress: [░░░░░░░░░░] 0%
 | Phase 01-foundation P04 | 19 | 2 tasks | 25 files |
 | Phase 01-foundation P03 | 9 | 2 tasks | 20 files |
 | Phase 02-agent-features P03 | 7 | 2 tasks | 7 files |
+| Phase 02-agent-features P02-01 | 9m 22s | 2 tasks | 15 files |
 
 ## Accumulated Context
 
@@ -83,6 +84,9 @@ Recent decisions affecting current work:
 - [Phase 02-agent-features]: meta-media://{media_id} placeholder URL at normalization time; actual download in adapter after tenant resolution
 - [Phase 02-agent-features]: WhatsApp thread_id = sender wa_id (WhatsApp has no threading; conversation scope is per phone number)
 - [Phase 02-agent-features]: Always return HTTP 200 to Meta webhooks regardless of processing errors to prevent retry storms
+- [Phase 02-agent-features]: pgvector/pgvector:pg16 Docker image required for pgvector extension — postgres:16-alpine does not include vector extension control file
+- [Phase 02-agent-features]: SentenceTransformer loaded as lazy singleton — model loaded once on first use to avoid per-call 2s overhead; 384d all-MiniLM-L6-v2 matches vector(384) column
+- [Phase 02-agent-features]: embed_and_store Celery task is fire-and-forget (ignore_result=True) — embedding backfill never blocks LLM response path
 
 ### Pending Todos
 
@@ -94,6 +98,6 @@ None yet.
 
 ## Session Continuity
 
-Last session: 2026-03-23T20:44:35.516Z
-Stopped at: Completed 02-agent-features/02-03-PLAN.md
+Last session: 2026-03-23T20:46:53.810Z
+Stopped at: Completed 02-agent-features/02-01-PLAN.md
 Resume file: None