docs(api): add API deprecation policy

[cvxluo]

DESCRIBE YOUR PR

Add our API Deprecation policy to our public develop docs. I thought the original Notion page was relatively hard to find, and don't see a reason this info needs to be private.

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Project	Deployment	Actions	Updated (UTC)
develop-docs	Ready	Preview, Comment	Mar 12, 2026 8:27pm

1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
sentry-docs	Ignored	Preview	Mar 12, 2026 8:27pm

[coolguyzone]

Looks good! Thanks for adding 🏄‍♂️