chore: commit pending phase-3 work and add TEST_ACCOUNTS.md

Includes planning artifacts (03-CONTEXT, 03-DISCUSSION-LOG, 03-02-SUMMARY),
integration test script, MinIO/auth/docker fixes, and local dev account reference.

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

docker-compose.yml

@@ -23,6 +23,7 @@ services:
       MINIO_ROOT_PASSWORD: ${MINIO_ROOT_PASSWORD}
       # RESEARCH.md Finding 3, T-03-09: allow browser CORS preflight for direct PUT uploads.
       MINIO_API_CORS_ALLOW_ORIGIN: ${CORS_ORIGINS:-http://localhost:5173}
+      MINIO_SERVER_URL: http://localhost:9000
     ports:
       - "9000:9000"
       - "9001:9001"
@@ -59,6 +60,11 @@ services:
       - MINIO_BUCKET=${MINIO_BUCKET}
       - MINIO_PUBLIC_ENDPOINT=${MINIO_PUBLIC_ENDPOINT:-localhost:9000}
       - REDIS_URL=${REDIS_URL}
+      - SECRET_KEY=${SECRET_KEY}
+      - ADMIN_EMAIL=${ADMIN_EMAIL}
+      - ADMIN_PASSWORD=${ADMIN_PASSWORD}
+      - CORS_ORIGINS=${CORS_ORIGINS:-http://localhost:5173}
+      - FRONTEND_URL=${FRONTEND_URL:-http://localhost:5173}
       - PYTHONDONTWRITEBYTECODE=1
     extra_hosts:
       - "host.docker.internal:host-gateway"