Summary

• keep the current CDP socket active until a replacement WebSocket has actually opened, and scope pending calls to the socket that owns them
• on Chrome’s explicit Session with given id not found rejection, perform one serialized reattach to a usable page (or create about:blank) and retry once
• restore Page, DOM, Runtime, and Network subscriptions on the replacement session so event-driven code keeps working
• deliberately do not replay commands after an ambiguous socket drop, where Chrome may already have applied the action
• cover concurrent stale-session failures, empty/internal target lists, dropped sockets, failed replacement connections, late closes from replaced sockets, and domain restoration

This ports the narrow, deterministic session-recovery behavior from the public browser-harness daemon while keeping transport-drop recovery conservative.

Validation

• bun test in packages/bcode-browser: 18 pass, 8 environment-gated skips
• bun typecheck in packages/bcode-browser
• root filtered typecheck: 13/13 packages pass
• bunx oxlint packages/bcode-browser/test/cdp-recovery.test.ts: clean
• recovery test file repeated 10 times without failure