Draft changelog: Aug 30 weekly entry for X API v2

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Summary

Adds an Aug 30, 2026 changelog entry covering product changes shipped since the Aug 13 entry.

Changes

• New features: filter qualifiers for X Activity API subscriptions, broadcast.start/broadcast.end events, and the GET /2/usage/credits endpoint
• Updates: pay-per-use monthly Post read cap raised from 2M to 3M, is_subscriber boolean on broadcast.chat payloads
• Docs-only PRs (nav fixes, link fixes, page repairs) were excluded

Context

Based on the 12 PRs merged to the docs repo since the last changelog entry; only end-user-facing product changes are included.

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Project	Status	Preview	Updated (UTC)
x-corp	🟢 Ready	View Preview	Aug 30, 2026, 8:08 PM

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