Bump bundled Weaviate to 1.39.13 (CVE-2026-111943, leaked eMudhra intermediates) #141

Weaviate 1.39.13 is 1.39.12 rebuilt on Go 1.26.10. That Go release makes crypto/x509 reject certificate chains that contain any of eight leaked eMudhra intermediate certificates (CVE-2026-111943, golang/go#82345). Weaviate makes outbound TLS calls for model modules, backups and OIDC.

The Compose files (docker-compose.dify-plus.yaml, the template, the generated docker-compose.yaml and docker-compose.middleware.yaml) pin 1.39.2, which predates the fix. 1.39.13 is a patch release in the same minor version, so there is no data or compatibility impact. The same bump is proposed upstream in langgenius/dify#44508. I'll open a PR.