Implement greet inbox and outbox

- Add user_greet model and startup table sync
- Implement /greet/user and /greet/delete handlers
- Implement noticeFriendGreeting inbox and noticeUserGreetingHistory outbox
- Return peer profile and center unit info for greeting notices
- Update login topInfo friend greet counters from unread inbox messages

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

internal/handler/greet/common.go

@@ -0,0 +1,40 @@
+package greet
+
+import (
+	"errors"
+	usermodel "honoka-chan/internal/model/user"
+	"honoka-chan/internal/session"
+	"strconv"
+)
+
+func resolveGreetingUserID(ss *session.Session, requestedUserID int) (int, error) {
+	if requestedUserID <= 0 {
+		return 0, errors.New("invalid user_id")
+	}
+
+	pref := usermodel.UserPref{}
+	has, err := ss.UserEng.Table(new(usermodel.UserPref)).
+		Where("invite_code = ?", strconv.Itoa(requestedUserID)).
+		Cols("user_id").
+		Get(&pref)
+	if err != nil {
+		return 0, err
+	}
+	if has && pref.UserID > 0 {
+		return pref.UserID, nil
+	}
+
+	user := usermodel.Users{}
+	has, err = ss.UserEng.Table(new(usermodel.Users)).
+		Where("user_id = ?", requestedUserID).
+		Cols("user_id").
+		Get(&user)
+	if err != nil {
+		return 0, err
+	}
+	if !has || user.UserID <= 0 {
+		return 0, errors.New("user not found")
+	}
+
+	return user.UserID, nil
+}