error_during_execution / cancelled is shown as a raw Run error #549

Problem

A claude-stream run (Claude or Grok) can end with this event in the transcript:

Run error: result subtype error_during_execution
cancelled

That is the raw stream-json result event dumped into the thread. The runner builds it here:

failText = `Run error: result subtype ${ev.subtype || "unknown"}`;
if (errors.length) {
  failText += `\n${errors.slice(-3).join("\n")}`;
}

(electron/runner.js, the type === "result" path.) subtype !== "success" always marks the thread failed and stores that string as lastError.

Session-lost (No conversation found) already gets a human follow-up line. cancelled does not. stopRun already leaves the thread idle with "Run stopped"; this path does the opposite for the same idea.

Impact

• The user sees adapter jargon (result subtype …) instead of a reason they can act on.
• A CLI-side cancel is treated as a crash: failed badge, Retry turn, lastError tooltip — not a stop.
• Known producer of this exact subtype on Grok: a permission prompt with no channel auto-cancels the first gated tool (issue Grok provider runs fail immediately after first assistant message #3; asking modes are now mapped to auto in electron/providers.js). If this still appears, either that mapping missed a mode or some other cancel (MCP, quota, user interrupt that still emitted a result event) is taking this path.

Fix direction

• Map known errors[] values before falling back to the subtype string. cancelled should look like a stop (idle + "Run stopped"), not a failure, unless we know it was an unrecoverable tool cancel.
• For remaining error_during_execution cases, surface the CLI errors[] (and stderr tail) as the message; keep the subtype out of user-facing copy.
• Distinct from Permission mode picker is a no-op or silent downgrade on grok, kimi, opencode and cursor #177 (permission pill is a no-op on grok/kimi/opencode) and from Grok provider runs fail immediately after first assistant message #3 (Grok died after the first message with no reason at all).