Add Web Channel for arbitrary Durable Objects

[cjol]

Summary

• add an ordinary Web Channel with an owned WebSockets capability for arbitrary Lifecycle Durable Objects
• dispatch AIChatAgent-compatible browser turns through the existing ChannelHost onMessage path and stream ChannelChunks back as AI SDK UI-message chunks
• make outbound chunk consumption abort-aware for transport cancellation
• add Web to the unchanged symmetric live adapter suite using a real Durable Object, WebSocketChatTransport observer, and Capn Web control session

Current scope

This first slice is live, non-resumable Web chat. Durable replay, server-owned transcript mutation, client-tool continuation, regeneration, multi-tab synchronization, and Agent migration remain deferred.

Validation

• pnpm --filter @cloudflare/channels test: 226 tests passed
• pnpm --filter @cloudflare/channels run build
• Web live suite: 5 scenarios passed against local Wrangler
• pnpm run check: exports, formatting, lint, and all 115 TypeScript projects passed

[changeset-bot]

🦋 Changeset detected

Latest commit: 5397be6

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@cloudflare/channels	Minor

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