헤더 검색 중앙 정렬·Resend 이메일 OTP·비밀번호 찾기 (v0.0.99)

Co-authored-by: Cursor <cursoragent@cursor.com>

db/migrations/018_email_otp_challenges.sql

@@ -0,0 +1,15 @@
+CREATE TABLE IF NOT EXISTS email_otp_challenges (
+  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  email TEXT NOT NULL,
+  purpose TEXT NOT NULL,
+  code_hash TEXT NOT NULL,
+  expires_at TIMESTAMPTZ NOT NULL,
+  consumed_at TIMESTAMPTZ,
+  verify_attempt_count INTEGER NOT NULL DEFAULT 0,
+  created_ip TEXT NOT NULL DEFAULT '',
+  created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+  CONSTRAINT email_otp_challenges_purpose_check CHECK (purpose IN ('signup', 'password_reset'))
+);
+
+CREATE INDEX IF NOT EXISTS email_otp_challenges_email_purpose_created_idx
+  ON email_otp_challenges (lower(email), purpose, created_at DESC);