v1.9.0

What's Changed

• docs: AI Multilingual v1.6.0 HTML user manual by @magpern in #51
• docs: relocate and refine v1.6.0 user manual by @magpern in #52
• docs: v1.6.0 user manual + Vlad acceptance checklist by @magpern in #53
• docs(cache): document anonymous-language cache contract (ADR-0024) by @magpern in #54
• docs: draft M5-A private CPT chrome integration plan by @magpern in #55
• feat(m5a): private CPT chrome integration public API (1.7.0) by @magpern in #56
• docs: add M5-A.1 public descriptor factory plan by @magpern in #57
• feat(integration): add public descriptor factory by @magpern in #58

Full Changelog: v1.6.0...v1.9.0