feat(ecosystem): add integration and cookbook hubs

[moonming]

Summary

• add bilingual Integration and Cookbook hubs backed by Markdown metadata, with navigation, JSON-LD, sitemap, canonical, and llms.txt support
• add a LocalAI Integration and Chat Completions Cookbook for the APISIX 3.18 openai-compatible provider, with separate client and upstream credentials and removal of alternative LocalAI authentication headers
• cover Redis-backed AI response caching, shared token counters, and distributed request quotas, plus a pinned two-node APISIX 3.18.0 and private Redis Open Source 8.10.1 lab
• add desktop and mobile browser coverage for both locales and all Integration and Cookbook routes

Validation

• Astro production build — 896 pages
• node scripts/generate-md-twins.mjs — 729 twins, 0 missing built pages
• content lint and internal link checks — 0 errors, 0 broken links
• sitemap generation and filters passed
• node scripts/assert-local-canonical-targets.mjs --dist dist — 896/896
• Playwright ecosystem suite — 10/10 desktop and mobile tests
• repository pre-commit hook (eslint and remark)
• Redis lab: Bash syntax and Docker Compose configuration checks, followed by a clean infrastructure preflight for two APISIX nodes, private Redis 8.10.1, Consumer authentication, and Redis Search
• two independent reviews found no remaining HIGH or MEDIUM issues

Publication boundary

The LocalAI pages remain validation-in-progress. The merged LocalAI guide and APISIX documentation PR #13770 cover a transparent proxy, including a recorded APISIX 3.17.0 and LocalAI 4.7.1 run. The native APISIX 3.18 openai-compatible Route in this PR is source-reviewed but not yet runtime-verified.

The Redis pages also remain validation-in-progress. Real provider call counters, complete and interrupted SSE cases, two clean functional runs with a second operator, sanitized log evidence, and a separate Redis-backed limit-count request-quota run remain release gates.

The Search-enabled Redis lab supports only linux/amd64 and linux/arm64, matching the pinned image's bundled-module builds.