Fix AI env passthrough and health check key mismatch

- docker-compose.prod.yml: add env_file to inject full .env into backend
  container (AI_ENABLED, AI_PROVIDER, OPENROUTER_API_KEY, etc. were missing)
- Config.tsx: fix health check key from 'anthropic' to 'ai'
  (backend returns checks.ai, not checks.anthropic)

docker-compose/docker-compose.prod.yml

@@ -16,6 +16,8 @@ services:
     user: "1000:1000"
     ports:
       - "${BACKEND_PORT:-8001}:8000"
+    env_file:
+      - .env
     environment:
       DATABASE_URL: postgresql+asyncpg://imago:imago@db:5432/imago
       REDIS_URL: redis://redis:6379/0

imago-admin/src/pages/admin/Config.tsx

@@ -122,7 +122,7 @@ export default function Config() {
                     <ConfigRow label="Base de données" value={health?.checks?.database?.status === 'ok' ? 'PostgreSQL — Connecté' : 'Non connecté'} readOnly />
                     <ConfigRow label="Redis" value={health?.checks?.redis?.status === 'ok' ? 'Redis 7 — Connecté' : 'Non connecté'} readOnly />
                     <ConfigRow label="OCR" value={health?.checks?.tesseract?.status === 'ok' ? 'Tesseract — Actif' : 'Non disponible'} readOnly />
-                    <ConfigRow label="AI Vision" value={health?.checks?.anthropic?.status === 'ok' ? 'Configuré' : 'Non configuré'} readOnly />
+                    <ConfigRow label="AI Vision" value={health?.checks?.ai?.status === 'ok' ? 'Configuré' : 'Non configuré'} readOnly />
                 </div>
             </section>
         </PageLayout>