fix(skydive): migrate author field from ObjectId to UUID string

- Register SkydiverProfile model in mysql.js (fixes startup crash on association)
- Replace $toObjectId with direct string match in all 12 aggregation queries
- Guard toJSONFor on all Mongo models to fall back to MySQL user.toProfileJSONFor()
  when author is a UUID string (restores username/image in API responses)
- Pass user to toJSONFor() everywhere instead of null
- Remove dead .populate('author') calls (author: String has no ref)
- Fix ownership check in /last route: compare author string to req.payload.id
  instead of the now-absent author.username property

src/services/mongo/clan.service.js

@@ -16,7 +16,6 @@ class ClanService {
                 .skip(Number(offset))
                 .limit(Number(limit))
                 .sort({ title: 'asc' })
-                .populate('author')
                 .exec(),
             HWClan.count(query).exec()
         ]).then(function (results) {
@@ -31,7 +30,6 @@ class ClanService {
 
     static async getClanById(id) {
         return HWClan.findOne({ id: id })
-            .populate('author')
             .then(function (clan) {
                 if (!clan) {
                     return null;
@@ -42,7 +40,6 @@ class ClanService {
 
     static async getClanByTitle(title) {
         return HWClan.findOne({ title: title })
-            .populate('author')
             .then(function (clan) {
                 if (!clan) {
                     return null;

src/services/mongo/member.service.js

@@ -16,7 +16,6 @@ class MemberService {
                 .skip(Number(offset))
                 .limit(Number(limit))
                 .sort({ name: 'asc' })
-                .populate('author')
                 .exec(),
             HWMember.count(query).exec()
         ]).then(function (results) {
@@ -31,7 +30,6 @@ class MemberService {
 
     static async getMemberById(id) {
         return HWMember.findOne({ id: id })
-            .populate('author')
             .then(function (member) {
                 if (!member) {
                     return null;
@@ -42,7 +40,6 @@ class MemberService {
 
     static async getMemberByName(name) {
         return HWMember.findOne({ name: name })
-            .populate('author')
             .then(function (member) {
                 if (!member) {
                     return null;