docs(integration): lakeFS, Hudi, Ray, Velero, Kopia guides + new AI category

[majinghe]

Summary

• Add five new RustFS integration guides in all five locales (en/zh/de/fr/ja), each verified end-to-end against RustFS v2.3.1 (write → confirm in RustFS → read back):
  • developer/integration/big-data/lakefs.md — lakeFS 1.58.0 repository on S3-compatible storage (force_path_style: true)
  • developer/integration/big-data/hudi.md — Apache Hudi 0.15.0 + Spark 3.5.6 writing a Hudi table to s3a://my-bucket
  • developer/integration/ai/ray.md — Ray 2.44 writing/reading Parquet via pyarrow S3FileSystem
  • developer/integration/backup/velero.md — Velero 1.16.2 + velero-plugin-for-aws backup/restore of cluster resources to RustFS
  • developer/integration/backup/kopia.md — Kopia 0.18.1 repository, snapshot and restore round-trip with SHA verification
• New developer/integration/ai/ category (index + meta.json, all locales) per request; Ray is its first entry.
• Update integration, backup, big-data category indexes and meta.json navigation in all locales.
• Screenshots: zh-locale console shots in zh docs, English shots in en/de/fr/ja.

Notes

• Kubeflow skipped: it is a full ML platform (Kubeflow Pipelines + Istio/Dex + multi-component control plane) that cannot be stood up and verified against a single-node RustFS endpoint in this test environment; per the "skip if not integrable" rule no guide was written.
• Documented real pitfalls: Kopia needs bare host:port endpoint + --disable-tls; lakeFS 1.x requires auth.encrypt.secret_key and force_path_style: true; Hudi needs KryoSerializer and the default key generator with empty partitionpath.field; Velero BSL must use the docker0 gateway (e.g. http://172.17.0.1:9000) so cluster pods can reach the host-side RustFS.

Validation

• node .agents/skills/localize-rustfs-docs/scripts/audit-locales.mjs --locales zh,de,fr,ja — only expected findings (de/fr/ja English-copy notice; SOURCE_LOCALE_LINK false positive from a docs.ray.io/en/… URL path)
• npm run docs:check — OK (7/7 checks)
• npm run build — OK (3135 files generated)
• All five integrations verified on a live RustFS v2.3.1 instance before writing docs.

[vercel]

@majinghe is attempting to deploy a commit to the overtrue's projects Team on Vercel.

A member of the Team first needs to authorize it.