Summary: post bridge adds API access

Why It Matters: This lets other tools connect with post bridge. It can make post bridge more useful for some users.

What Changed:

• post bridge added an "API" link to its main menu.
• post bridge added a new section called "Developer API" with details about building with post bridge.
• The "Starter" pricing plan was removed.
• The "Creator" and "Pro" pricing plans now say "API add-on available."
• The number of happy customers changed from 1,407 to 1,412.
• The number of posts published by users changed from 608,601 to 611,578.