chore(templates): align nsfw metadata

[cuisongliu]

Summary

• align nsfw template readme URL with the repository-maintained README
• add zh readme metadata for nsfw
• keep the existing explicit ethandai4869/nsfw-auth:latest image reference unchanged

Scope

Included project:

• nsfw

Skipped from this worker scope:

• kuboard: only raw URL owner/branch differences after normalization
• llama2-chinese: only raw URL owner/branch and newline differences
• llama3-8b-chinese: only draft: true plus formatting/raw URL differences; skipped to avoid changing template visibility in this low-burden batch
• lobe-chat: only raw URL owner/branch and formatting differences
• loki: kb-0.9 reference would roll busybox:1.36.1 back to busybox:latest
• midjourney-ui: formatting/raw URL differences only
• netbird: raw URL differences only in index and README files
• node-red: raw URL differences only
• open-webui: raw URL differences only

Validation

• ruby -e 'require "yaml"; docs=YAML.load_stream(File.read("template/nsfw/index.yaml")); abort "empty" if docs.empty?; puts docs.map { |d| d["kind"] }.join(",")'
• local platform metadata validation equivalent to .github/workflows/build-template-cluster-image.yaml
• local changed-target matrix simulation for template/nsfw/index.yaml
• git diff --check
• rg -n "labring-actions/templates|/kb-0\\.9/|raw\\.githubusercontent\\.com" template/nsfw/index.yaml

[cuisongliu]

Closing this first-batch metadata-only PR because nsfw also has image/platform follow-up work (only latest, amd64-only). To keep each project in a single PR, nsfw should move to the later image/platform batch instead of splitting metadata and image changes.