feat: add Delete key support (forward delete)

src/components/Input.tsx

@@ -91,17 +91,29 @@ export function Input({ onSubmit, historyValue, onHistoryNavigate }: InputProps)
     }
 
     // Option+Backspace (Mac) / Ctrl+Backspace (Windows) - delete word backward
-    if ((key.meta || key.ctrl) && (key.backspace || key.delete)) {
+    if ((key.meta || key.ctrl) && key.backspace) {
       actions.deleteWordBackward();
       return;
     }
 
-    // Handle backspace/delete - delete character before cursor
-    if (key.backspace || key.delete) {
+    // Option+Delete (Mac) / Ctrl+Delete (Windows) - delete word forward
+    if ((key.meta || key.ctrl) && key.delete) {
+      actions.deleteWordForward();
+      return;
+    }
+
+    // Backspace - delete character before cursor
+    if (key.backspace) {
       actions.deleteBackward();
       return;
     }
 
+    // Delete - delete character at cursor
+    if (key.delete) {
+      actions.deleteForward();
+      return;
+    }
+
     // Shift+Enter - insert newline for multi-line input
     if (key.return && key.shift) {
       actions.insert('\n');

src/hooks/useTextBuffer.ts

@@ -1,13 +1,17 @@
 import { useRef, useState, useCallback } from 'react';
-import { findPrevWordStart } from '../utils/text-navigation.js';
+import { findPrevWordStart, findNextWordEnd } from '../utils/text-navigation.js';
 
 export interface TextBufferActions {
   /** Insert text at the current cursor position */
   insert: (text: string) => void;
   /** Delete the character before the cursor */
   deleteBackward: () => void;
+  /** Delete the character at the cursor */
+  deleteForward: () => void;
   /** Delete from cursor back to start of previous word */
   deleteWordBackward: () => void;
+  /** Delete from cursor forward to end of next word */
+  deleteWordForward: () => void;
   /** Move cursor to an absolute position (clamped to valid range) */
   moveCursor: (position: number) => void;
   /** Clear the buffer and reset cursor to 0 */
@@ -60,6 +64,15 @@ export function useTextBuffer(): UseTextBufferResult {
       }
     },
 
+    deleteForward: () => {
+      if (cursorPos.current < buffer.current.length) {
+        buffer.current =
+          buffer.current.slice(0, cursorPos.current) +
+          buffer.current.slice(cursorPos.current + 1);
+        rerender();
+      }
+    },
+
     deleteWordBackward: () => {
       if (cursorPos.current > 0) {
         const wordStart = findPrevWordStart(buffer.current, cursorPos.current);
@@ -71,6 +84,16 @@ export function useTextBuffer(): UseTextBufferResult {
       }
     },
 
+    deleteWordForward: () => {
+      if (cursorPos.current < buffer.current.length) {
+        const wordEnd = findNextWordEnd(buffer.current, cursorPos.current);
+        buffer.current =
+          buffer.current.slice(0, cursorPos.current) +
+          buffer.current.slice(wordEnd);
+        rerender();
+      }
+    },
+
     moveCursor: (position: number) => {
       cursorPos.current = Math.max(0, Math.min(buffer.current.length, position));
       rerender();