fix(kestra): load flows via kestra-init one-shot container

--flow-path is not a valid Kestra flag; flows must be pushed explicitly.
kestra-init waits for Kestra to pass its healthcheck then runs
'kestra flow namespace update schoolcompare.data /flows --no-delete'
to import all flow YAMLs. Runs once on stack start; --no-delete means
any flows created manually in the UI are not removed.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -82,12 +82,11 @@ services:
   kestra:
     image: kestra/kestra:latest
     container_name: schoolcompare_kestra
-    command: server standalone --flow-path=/flows
+    command: server standalone
     ports:
       - "8080:8080"
     volumes:
       - kestra_storage:/app/storage
-      - ./integrator/flows:/flows
     environment:
       KESTRA_CONFIGURATION: |
         datasources:
@@ -111,6 +110,44 @@ services:
     networks:
       - schoolcompare-network
     restart: unless-stopped
+    healthcheck:
+      test: ["CMD-SHELL", "curl -sf http://localhost:8080/api/v1/flows/search || exit 1"]
+      interval: 15s
+      timeout: 10s
+      retries: 10
+      start_period: 60s
+
+  # One-shot container: imports flow YAMLs into Kestra after it's healthy
+  kestra-init:
+    image: kestra/kestra:latest
+    container_name: schoolcompare_kestra_init
+    volumes:
+      - ./integrator/flows:/flows:ro
+    environment:
+      KESTRA_CONFIGURATION: |
+        datasources:
+          postgres:
+            url: jdbc:postgresql://db:5432/kestra
+            driverClassName: org.postgresql.Driver
+            username: schoolcompare
+            password: schoolcompare
+        kestra:
+          repository:
+            type: postgres
+          queue:
+            type: postgres
+          storage:
+            type: local
+            local:
+              base-path: /tmp/kestra-init-storage
+    command: >
+      flow namespace update schoolcompare.data /flows --no-delete
+    depends_on:
+      kestra:
+        condition: service_healthy
+    networks:
+      - schoolcompare-network
+    restart: no
 
   # Data integrator — Python microservice called by Kestra
   integrator: