feat(gyeol): Q6Step (자유 의견 textarea) + Q7Step (이메일 옵션)

- Q6: 1000자 textarea, 빈 칸 허용 (skippable)
- Q7: yes/no 라디오 + yes 선택 시 이메일 입력 노출 + 형식 validation
- Q7 onSubmit = 최종 제출 트리거 (page.tsx에서 POST /api/survey)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/gyeol/components/Q6Step.tsx

@@ -0,0 +1,34 @@
+'use client';
+
+import { useState } from 'react';
+import type { SurveyResponse } from '@/lib/survey/types';
+import QuestionLayout from './QuestionLayout';
+
+interface Props {
+  initial: Partial<SurveyResponse>;
+  onPrev: () => void;
+  onNext: (partial: Partial<SurveyResponse>) => void;
+}
+
+export default function Q6Step({ initial, onPrev, onNext }: Props) {
+  const [text, setText] = useState(initial.free_opinion ?? '');
+
+  // 빈 칸 허용 (skippable)
+  return (
+    <QuestionLayout
+      step="q6"
+      onPrev={onPrev}
+      onNext={() => onNext({ free_opinion: text.trim() || undefined })}
+    >
+      <textarea
+        value={text}
+        onChange={(e) => setText(e.target.value)}
+        placeholder="자유롭게 적어주세요. (선택)"
+        maxLength={1000}
+        rows={6}
+        className="w-full px-4 py-3 rounded-xl bg-white/[0.04] border border-white/15 text-white placeholder:text-white/30 focus:border-white/40 focus:outline-none resize-none"
+      />
+      <p className="mt-2 text-xs text-white/40 text-right font-mono">{text.length}/1000</p>
+    </QuestionLayout>
+  );
+}

app/gyeol/components/Q7Step.tsx

@@ -0,0 +1,105 @@
+'use client';
+
+import { useState } from 'react';
+import type { SurveyResponse } from '@/lib/survey/types';
+import QuestionLayout from './QuestionLayout';
+
+interface Props {
+  initial: Partial<SurveyResponse>;
+  onPrev: () => void;
+  onSubmit: (partial: Partial<SurveyResponse>) => void;
+  submitting: boolean;
+}
+
+export default function Q7Step({ initial, onPrev, onSubmit, submitting }: Props) {
+  const [wantEmail, setWantEmail] = useState<'yes' | 'no' | ''>(
+    initial.email ? 'yes' : ''
+  );
+  const [email, setEmail] = useState(initial.email ?? '');
+
+  // 'no' 선택 시 즉시 전송 가능. 'yes' 선택 시 이메일 유효성 필요.
+  const emailValid = /\S+@\S+\.\S+/.test(email);
+  const canSubmit =
+    wantEmail === 'no' || (wantEmail === 'yes' && emailValid);
+
+  function handleSubmit() {
+    onSubmit({
+      email: wantEmail === 'yes' && emailValid ? email.trim() : undefined,
+    });
+  }
+
+  return (
+    <QuestionLayout
+      step="q7"
+      onPrev={onPrev}
+      onNext={handleSubmit}
+      nextDisabled={!canSubmit}
+      nextLabel="전송"
+      submitting={submitting}
+    >
+      <div className="space-y-3">
+        <label
+          className={`flex items-center gap-3 px-4 py-3.5 rounded-xl border cursor-pointer transition ${
+            wantEmail === 'yes'
+              ? 'border-violet-400 bg-violet-400/10'
+              : 'border-white/15 bg-white/[0.02] hover:border-white/30'
+          }`}
+        >
+          <input
+            type="radio"
+            name="want_email"
+            checked={wantEmail === 'yes'}
+            onChange={() => setWantEmail('yes')}
+            className="sr-only"
+          />
+          <span
+            className={`w-4 h-4 rounded-full border-2 flex items-center justify-center flex-shrink-0 ${
+              wantEmail === 'yes' ? 'border-violet-400' : 'border-white/30'
+            }`}
+          >
+            {wantEmail === 'yes' && <span className="w-2 h-2 rounded-full bg-violet-400" />}
+          </span>
+          <span className="text-sm text-white">네, 알려주세요</span>
+        </label>
+
+        {wantEmail === 'yes' && (
+          <input
+            type="email"
+            value={email}
+            onChange={(e) => setEmail(e.target.value)}
+            placeholder="your@email.com"
+            maxLength={200}
+            className="w-full px-4 py-3 rounded-xl bg-white/[0.04] border border-white/15 text-white placeholder:text-white/30 focus:border-white/40 focus:outline-none"
+          />
+        )}
+
+        <label
+          className={`flex items-center gap-3 px-4 py-3.5 rounded-xl border cursor-pointer transition ${
+            wantEmail === 'no'
+              ? 'border-violet-400 bg-violet-400/10'
+              : 'border-white/15 bg-white/[0.02] hover:border-white/30'
+          }`}
+        >
+          <input
+            type="radio"
+            name="want_email"
+            checked={wantEmail === 'no'}
+            onChange={() => {
+              setWantEmail('no');
+              setEmail('');
+            }}
+            className="sr-only"
+          />
+          <span
+            className={`w-4 h-4 rounded-full border-2 flex items-center justify-center flex-shrink-0 ${
+              wantEmail === 'no' ? 'border-violet-400' : 'border-white/30'
+            }`}
+          >
+            {wantEmail === 'no' && <span className="w-2 h-2 rounded-full bg-violet-400" />}
+          </span>
+          <span className="text-sm text-white">됐어요</span>
+        </label>
+      </div>
+    </QuestionLayout>
+  );
+}