Add SMS consent logging for Twilio compliance

Log phone, IP, and user agent to sms_consents table before sending
verification SMS. Add disclosure text to login form.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

db/models.go

@@ -54,6 +54,14 @@ type Slot struct {
 	SortOrder int64
 }
 
+type SmsConsent struct {
+	ID        int64
+	Phone     string
+	IpAddress string
+	UserAgent string
+	CreatedAt time.Time
+}
+
 type User struct {
 	ID        int64
 	Phone     sql.NullString

db/queries.sql

@@ -132,3 +132,6 @@ SELECT * FROM rsvps WHERE id = ?;
 
 -- name: UpdateRsvp :exec
 UPDATE rsvps SET name = ?, note = ?, plus_one = ? WHERE id = ?;
+
+-- name: CreateSmsConsent :exec
+INSERT INTO sms_consents (phone, ip_address, user_agent) VALUES (?, ?, ?);

db/queries.sql.go

@@ -181,6 +181,21 @@ func (q *Queries) CreateSlot(ctx context.Context, arg CreateSlotParams) (Slot, e
 	return i, err
 }
 
+const createSmsConsent = `-- name: CreateSmsConsent :exec
+INSERT INTO sms_consents (phone, ip_address, user_agent) VALUES (?, ?, ?)
+`
+
+type CreateSmsConsentParams struct {
+	Phone     string
+	IpAddress string
+	UserAgent string
+}
+
+func (q *Queries) CreateSmsConsent(ctx context.Context, arg CreateSmsConsentParams) error {
+	_, err := q.db.ExecContext(ctx, createSmsConsent, arg.Phone, arg.IpAddress, arg.UserAgent)
+	return err
+}
+
 const createUserByEmail = `-- name: CreateUserByEmail :one
 INSERT INTO users (email, name) VALUES (?, '') RETURNING id, phone, email, name, created_at
 `