feat(tui): double ESC discards the draft, even mid-stream

Mirrors the CLI binding. Placed above the isBlocked early-return so it
works while the agent streams — that is the whole gap, since Ctrl+C
interrupts a running turn and only clears the composer when idle.

Pushes the draft to history before clearing so Up recalls it.

ui-tui/src/app/useInputHandlers.ts

@@ -3,7 +3,7 @@ import { useStore } from '@nanostores/react'
 import { useEffect, useRef } from 'react'
 
 import { DASHBOARD_TUI_MODE } from '../config/env.js'
-import { TYPING_IDLE_MS } from '../config/timing.js'
+import { DOUBLE_ESC_MS, TYPING_IDLE_MS } from '../config/timing.js'
 import { applyCompletion } from '../domain/slash.js'
 import type {
   ApprovalRespondResponse,
@@ -320,9 +320,33 @@ export function useInputHandlers(ctx: InputHandlerContext): InputHandlerResult {
       })
   }
 
+  // Double-Esc discards the draft, matching Claude Code / Gemini CLI. It
+  // sits above the isBlocked early-return on purpose: Ctrl+C interrupts a
+  // running turn rather than clearing, so while the agent streams there is
+  // otherwise no way to throw away a half-typed prompt. The draft is pushed
+  // to history first so Up recalls it.
+  const lastEscRef = useRef(0)
+
   useInput((ch, key) => {
     const live = getUiState()
 
+    if (key.escape) {
+      const now = Date.now()
+      const isDouble = now - lastEscRef.current <= DOUBLE_ESC_MS
+
+      lastEscRef.current = isDouble ? 0 : now
+
+      if (isDouble && (cState.input || cState.inputBuf.length)) {
+        if (cState.input.trim()) {
+          cActions.pushHistory(cState.input)
+        }
+
+        cActions.clearIn()
+
+        return
+      }
+    }
+
     if (isBlocked) {
       // When approval/clarify/confirm overlays are active, their own useInput
       // handlers must receive keystrokes (arrow keys, numbers, Enter).  Only

ui-tui/src/config/timing.ts

@@ -12,3 +12,9 @@ export const REASONING_PULSE_MS = 700
 // responsive enough to track the drag, cheap enough to stay smooth, and the
 // trailing edge always lands the final width so the settled layout is exact.
 export const RESIZE_COALESCE_MS = 32
+
+// Two Esc presses within this window discard the draft (Claude Code /
+// Gemini CLI parity). Long enough for a deliberate double-tap, short
+// enough that two unrelated Escs — dismissing a completion, then a
+// selection — don't silently clear the composer.
+export const DOUBLE_ESC_MS = 500