[Bug] Esc key interrupt disabled when queued messages or background tasks exist

Bug Description
BUG: Esc to interrupt doesn't work when queued messages or background tasks exist
The spinner shows "(esc to interrupt)" but pressing Esc does absolutely nothing when:

There are queued messages ("Press up to edit queued messages")
Background tasks are running (e.g. "3 background tasks")

This is caused by the 2.1.0 change "Fixed Esc key with queued prompts to only move them to input without canceling the running task" - but the UI still tells users to press Esc to interrupt!
Expected: Either Esc should interrupt the running task as the UI suggests, OR the UI should say "(ctrl+c to interrupt)" instead of "(esc to interrupt)" when queued messages exist.
Current behavior: User presses Esc repeatedly, nothing happens, task continues running for 30+ minutes with no way to stop it except Ctrl+C (which isn't mentioned in the UI).
Environment: macOS, Claude Code v2.1.1, Opus 4.5

Environment Info

• Platform: darwin
• Terminal: vscode
• Version: 2.1.1
• Feedback ID: 3d99d302-71c8-45f4-bdcf-c831a089bc31

Errors

[{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/lohonyaigyozo/.local/share/claude/versions/2.1.1 (expected in multi-process scenarios)\n    at oXR (/$bunfs/root/claude:2994:2164)\n    at WKA (/$bunfs/root/claude:2994:1884)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-08T16:58:50.102Z"}]