fix: allow session cancellation in all states

Previously cancellation only worked in 'selecting' or 'ordering' states.
Now users can cancel server consultation at any stage using keywords:
취소, 다시, 처음, 리셋, 초기화, 다시 시작, 처음부터

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

vitest.config.ts

@@ -4,17 +4,7 @@ import path from 'path';
 export default defineConfig({
   test: {
     globals: true,
-    environment: 'miniflare',
-    environmentOptions: {
-      bindings: {
-        BOT_TOKEN: 'test-bot-token',
-        WEBHOOK_SECRET: 'test-webhook-secret',
-        OPENAI_API_KEY: 'test-openai-key',
-        DEPOSIT_ADMIN_ID: '999999999',
-      },
-      kvNamespaces: ['RATE_LIMIT_KV'],
-      d1Databases: ['DB'],
-    },
+    environment: 'node',
     setupFiles: ['./tests/setup.ts'],
     coverage: {
       provider: 'v8',