webui: Add user birthday settings

- Store birth month and day in user_pref with default 10/18
- Migrate existing user_pref rows to fill missing birthday fields
- Expose birthday editing in the webui profile page
- Replace hardcoded birthday values in user info, top info, and product list responses
- Fix birthday month/day field alignment in the profile form

Signed-off-by: Sean Du <do4suki@gmail.com>

internal/handler/ghome/account/login.go

@@ -278,6 +278,8 @@ func addUser(dbSession *xorm.Session, phone, password string, isDefault bool) (g
 				SnsCoin:          usermodel.DefaultUserSnsCoin,
 				EnergyMax:        usermodel.DefaultUserEnergyMax,
 				OverMaxEnergy:    usermodel.DefaultUserOverMaxEnergy,
+				BirthMonth:       usermodel.DefaultBirthMonth,
+				BirthDay:         usermodel.DefaultBirthDay,
 				ProfileVersion:   usermodel.CurrentUserPrefProfileVersion,
 				UpdateTime:       time.Now().Unix(),
 			}