Session-not-found errors are only detected in the exact V1 shape, other wrappers are missed

Description

isSessionNotFoundError / isLocalSessionNotFoundError in the app only recognise the exact V1 tagged shape (_tag === "SessionNotFoundError" with matching sessionID) and the exact local Error.message. When the server returns session-deletion errors through other wrappers — a plain string body, an object with name: "NotFoundError" and data.message, or any serialised object whose message contains the not-found text — the detector misses it, so UI code that should treat the session as gone (hide the entry, stop retrying, drop references) instead keeps it or shows a generic failure.

Plugins

N/A

OpenCode version

dev (current upstream/dev)

Steps to reproduce

1. Open a session, then delete it on the server (or let a worker remove it).
2. Trigger a request against the deleted session (rename, load, switch).
3. The error arrives shaped as a string "Session not found: <id>" or as a NotFoundError object. isSessionNotFoundError returns false, so the app does not route to the "session gone" handling and surfaces a generic error.

Screenshot and/or share link

N/A

Operating System

Windows 11 (platform-independent)

Terminal

N/A (app UI / desktop)

Related / duplicate check

• No open issue matches this specific error-shape detection gap; verified by search.