Draft changelog: streaming latency and new auth options

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Summary

Adds a Sep 7, 2026 changelog entry covering user-facing X API v2 changes shipped since the Sep 1 entry.

Changes

• Streaming endpoints P99 latency improved from ~6-7 seconds to ~4-5 seconds.
• Webhooks management endpoints (/2/webhooks) now accept OAuth 2.0 user context.
• X Activity API subscription endpoints (PUT/DELETE /2/activity/subscriptions/:subscription_id) now accept OAuth 1.0a and OAuth 2.0 user context.

Context

Reviewed all merges to main since the last changelog entry (Sep 1). All were automated OpenAPI spec syncs; the changes above are the user-facing deltas. Media size/duration limit changes in the same window were already covered by the Sep 1 entry.

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Project	Status	Preview	Updated
x-corp	🟢 Ready	View Preview	Sep 7, 2026, 5:17 PM

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