webui: Make some user preferences configurable

This extends 09f0237560.

- Extend user_pref with configurable profile fields and automatic migration defaults
- Move user info responses to read from user_pref instead of hardcoded values
- Add admin profile page for editing UI values after login

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

internal/handler/live/continue.go

@@ -16,8 +16,8 @@ func continuee(ctx *gin.Context) {
 
 	ss.Respond(liveschema.ContinueResp{
 		ResponseData: liveschema.ContinueData{
-			BeforeSnsCoin:   100000,
-			AfterSnsCoin:    100000,
+			BeforeSnsCoin:   ss.UserPref.SnsCoin,
+			AfterSnsCoin:    ss.UserPref.SnsCoin,
 			ServerTimestamp: time.Now().Unix(),
 		},
 		ReleaseInfo: []any{},