Draft changelog: Aug 28 weekly roundup

[mintlify]

Summary

Adds a changelog entry covering product changes shipped since the Aug 13 entry.

Changes

• New features: Chat API bot accounts (/2/bots), X Ads MCP server, broadcast.start/broadcast.end events and filter.qualifiers for the X Activity API, GET /2/usage/credits, and delete Chat messages endpoint.
• Updates: pay-per-use monthly Post cap raised from 2M to 3M, is_subscriber added to broadcast.chat payloads.
• Docs-only fixes (blank page fix, nav/link corrections, customer directory) were excluded.

Context

Based on PRs merged to xdevplatform/docs between Aug 13 and Aug 28, 2026.

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Project	Status	Preview	Updated (UTC)
x-corp	🟢 Ready	View Preview	Aug 28, 2026, 1:45 AM

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