• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Currently the double-Esc interrupt window in the TUI prompt is hardcoded to 5000ms (packages/opencode/src/cli/cmd/tui/component/prompt/index.tsx). Users can't tune it: too short causes accidental aborts, too long makes cancel feel sluggish, and there are no guardrails.

Proposal:

• Add a config field session_interrupt_timeout_ms with default 5000ms.
• Validate bounds: min 500ms, max 10000ms; reject out-of-range values.
• Wire it into the TUI interrupt timer so the window follows the config.
• Document in the config reference.
• Note: desktop and VS Code don't currently implement the double-Esc window; TUI is first, and those clients can adopt the same setting in follow-ups.

Acceptance:

• Default behavior remains 5000ms.
• Setting a value within bounds changes the double-Esc window accordingly.
• Out-of-range values are rejected with a clear error.