feat: brain-engine + brain-ui + docs — template full stack standalone

- brain-engine: server, embed, search, RAG, MCP, start.sh (standalone)
- brain-ui: source React complète, build.sh, DocsView avec tier colors
- docs: 14 pages guides humains (getting-started, architecture, sessions, workflows, agents, vues tier)
- brain-compose.yml v0.9.0: tier featured ajouté, sessions/agents par tier, coach_level, API key schema
- DISTRIBUTION_CHECKLIST v1.2: brain-engine + brain-ui + docs dans la checklist

brain-engine/queries/graduation-candidates.sql

@@ -0,0 +1,16 @@
+-- graduation-candidates.sql — Patterns L3a prêts pour graduation vers L3b (toolkit)
+-- Usage : sqlite3 brain.db < brain-engine/queries/graduation-candidates.sql
+
+SELECT
+    agent,
+    projet,
+    stack,
+    pattern_id,
+    validations,
+    seuil_graduation,
+    ROUND(CAST(validations AS REAL) / seuil_graduation * 100) || '%' AS progress,
+    last_validated
+FROM agent_memory
+WHERE graduated = 0
+  AND validations >= seuil_graduation
+ORDER BY validations DESC;