docs: fit meta titles and descriptions to search-engine limits

[himanshu-lal4]

Bing Webmaster's SEO analysis flags every docs page: rendered <title>s run 90–120 chars (limit ~65) and meta descriptions 120–350 chars (limit ~160), because the keyword-rich front-matter titles get the | React Native Liquid Glass suffix appended by jekyll-seo-tag.

This trims front matter only on all 16 pages:

• rendered titles now 31–63 chars including the suffix (the suffix keeps the primary keyword in every title)
• descriptions now 124–158 chars, keywords front-loaded
• visible content untouched — page.html never renders page.title as an H1, so the long keyword-rich H1s on each page stay exactly as they were

Docs-only, so native builds skip via the changes gate.