Draft changelog: Aug 31 weekly X API updates

[mintlify]

Summary

Adds an Aug 31, 2026 changelog entry covering product changes shipped since the Aug 13 entry.

Changes

• New: filter.qualifiers on X Activity API subscriptions (conversation_type, direction)
• New: broadcast.start and broadcast.end events in the X Activity API
• New: GET /2/usage/credits endpoint for PPU credit balance
• Update: is_subscriber field on broadcast.chat event payloads

Context

Sourced from PRs merged to xdevplatform/docs since the last changelog entry (#342, #340, #329, #324). Docs-only fixes (nav additions, page fixes, formatting) were excluded.

[mintlify]

Preview deployment for your docs. Learn more about Mintlify Previews.

Project	Status	Preview	Updated (UTC)
x-corp	🟢 Ready	View Preview	Aug 31, 2026, 5:12 PM

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}