Draft changelog: block endpoints, subscription events, broadcast scopes

[mintlify]

Summary

Adds a Sep 9, 2026 changelog entry covering product changes shipped since the last entry (Sep 1).

Changes

• New Enterprise-only block and unblock user endpoints (POST /2/users/{id}/blocking, DELETE /2/users/{source_user_id}/blocking/{target_user_id})
• New subscriptions.subscribe / subscriptions.unsubscribe events for the X Activity API, with direction qualifier and follows.read scope requirement
• New broadcast.read and broadcast.write OAuth 2.0 scopes

Context

Based on PRs #404, #402, and #350, merged since the last changelog entry.

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Project	Status	Preview	Updated
x-corp	🟢 Ready	View Preview	Sep 9, 2026, 11:09 PM

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