Dispatch cannot start or message Code sessions — persistent session_stale_relogin

Dispatch (Cowork research preview) on macOS. Mid-evening 2026-07-11, after ~5 successful code-session spawns the same night, every start_code_task and send_message to code sessions began failing with: "Unable to start session. Sign in again to continue: session_stale_relogin".

Ruled out: CLI /login with subscription account (terminal /rc works fine after), full /logout-/login cycle, desktop app sign-out/sign-in, desktop app + CLI updates, full Mac reboot, re-pairing (phone sign-out, Dispatch toggle off/on, sign back in), second phone. Cowork (non-code) task sessions spawn and run normally throughout — failure is isolated to the Dispatch-to-Code bridge.

Separate mobile UI bug: Dispatch tab compose field does not clear after sending (reproduces on two phones, current version)