docs: add GLM-5.2 API offer details

[ai-bankofai]

Summary

• Add GLM-5.2 limited-time API offer details to English and Chinese model pages
• Add the same offer notice to English and Chinese pricing pages
• Clarify the August 12, 2026 start date and API-only eligibility
• Document the 60% settlement rates for input, cache write, cache read, and output
• Bump package version from 1.3.16 to 1.3.17

Verification

• yarn build