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/metabolism-dashboard.sql

@@ -0,0 +1,24 @@
+-- metabolism-dashboard.sql — Vue santé brain sur 7 jours
+-- Usage : sqlite3 brain.db < brain-engine/queries/metabolism-dashboard.sql
+
+-- Ratio use-brain / build-brain sur 7 jours
+SELECT
+    COUNT(*) AS sessions_7d,
+    SUM(CASE WHEN type = 'build-brain' THEN 1 ELSE 0 END) AS build_brain,
+    SUM(CASE WHEN type = 'use-brain'   THEN 1 ELSE 0 END) AS use_brain,
+    ROUND(
+        CAST(SUM(CASE WHEN type='use-brain' THEN 1 ELSE 0 END) AS REAL) /
+        NULLIF(SUM(CASE WHEN type='build-brain' THEN 1 ELSE 0 END), 0),
+    2) AS ratio_use_build,
+    ROUND(AVG(health_score), 2) AS avg_health_score,
+    CASE
+        WHEN ROUND(CAST(SUM(CASE WHEN type='use-brain' THEN 1 ELSE 0 END) AS REAL) /
+             NULLIF(SUM(CASE WHEN type='build-brain' THEN 1 ELSE 0 END), 0), 2) >= 1.0
+        THEN '✅ équilibré'
+        WHEN ROUND(CAST(SUM(CASE WHEN type='use-brain' THEN 1 ELSE 0 END) AS REAL) /
+             NULLIF(SUM(CASE WHEN type='build-brain' THEN 1 ELSE 0 END), 0), 2) >= 0.5
+        THEN '⚠️  à surveiller'
+        ELSE '🔴 boucle narcissique'
+    END AS verdict
+FROM sessions
+WHERE date >= date('now', '-7 days');