Enable and fix /buddy command

The /buddy command was completely disabled by bun:bundle feature('BUDDY')
flag which evaluates to false at runtime. Removed all feature('BUDDY')
checks across the codebase to register the command, and added keyboard
event handling (q/Enter to dismiss) which was missing from the UI.

src/buddy/useBuddyNotification.tsx

@@ -1,5 +1,4 @@
 import { c as _c } from "react/compiler-runtime";
-import { feature } from 'bun:bundle';
 import React, { useEffect } from 'react';
 import { useNotifications } from '../context/notifications.js';
 import { Text } from '../ink.js';
@@ -50,9 +49,6 @@ export function useBuddyNotification() {
   let t1;
   if ($[0] !== addNotification || $[1] !== removeNotification) {
     t0 = () => {
-      if (!feature("BUDDY")) {
-        return;
-      }
       const config = getGlobalConfig();
       if (config.companion || !isBuddyTeaserWindow()) {
         return;
@@ -80,7 +76,6 @@ export function findBuddyTriggerPositions(text: string): Array<{
   start: number;
   end: number;
 }> {
-  if (!feature('BUDDY')) return [];
   const triggers: Array<{
     start: number;
     end: number;