fix(server): reset session status to idle when async prompt fails

Description

When an async prompt fails, the session status remains stuck in a running state instead of being reset to idle.

Reproduction Steps

1. Start an async prompt that fails (e.g., tool error, provider error)
2. Observe session status remains in running/error state
3. Session never returns to idle

Expected Behavior

Session status should be reset to idle when async prompt fails, allowing new prompts to be sent.

Actual Behavior

Session status stuck, blocking new prompts.

System Info

• OS: Linux/macOS/Windows
• opencode version: dev

Fix

Add yield* statusSvc.set(ctx.params.sessionID, { type: "idle" }).pipe(Effect.ignore) in the error handler of the async prompt handler.