docs: sync README + migrate example to v0.1.1 field names (#3)

The SDK landed v0.1.1 with the correct Pydantic field names for
PageInfo (the real API returns title/likes_count/followers_count/bio,
not the name/likes/followers/about I'd guessed in v0.1.0). The
landing repo's README + example still used the old names, so anyone
following the migration guide would hit AttributeError.

Fixes:
  page.name      → page.title
  page.likes     → page.likes_count
  page.followers → page.followers_count
  page.verified  → dropped (no equivalent in real response)
  page.about     → page.bio

README quickstart + side-by-side migration block, plus
examples/migrate.py print section — all updated to match.