Normalize file names before using them as keys

On macOS the filenames on disk are stored in NFD form. When the original
filename on the server was in NFC form, the filenames wouldn't match,
and a MOVE or DELETE+PUT would be triggered.

This changes converts all filenames to NFC form during local discovery.

src/libsync/discovery.cpp

@@ -82,7 +82,8 @@ void ProcessDirectoryJob::process()
     };
     std::map<QString, Entries> entries;
     for (auto &e : _serverNormalQueryEntries) {
-        entries[e.name].serverEntry = std::move(e);
+        // Keep the name on the server as-is, but use the NFC form as the key
+        entries[e.name.normalized(QString::NormalizationForm_C)].serverEntry = std::move(e);
     }
     _serverNormalQueryEntries.clear();
 
@@ -93,7 +94,7 @@ void ProcessDirectoryJob::process()
             if (rec.isVirtualFile() && isVfsWithSuffix()) {
                 name = chopVirtualFileSuffix(name);
             }
-            auto &dbEntry = entries[name].dbEntry;
+            auto &dbEntry = entries[name.normalized(QString::NormalizationForm_C)].dbEntry;
             dbEntry = rec;
             setupDbPinStateActions(dbEntry);
         })) {
@@ -102,6 +103,7 @@ void ProcessDirectoryJob::process()
     }
 
     for (auto &e : _localNormalQueryEntries) {
+        e.name = e.name.normalized(QString::NormalizationForm_C);
         entries[e.name].localEntry = e;
     }
     if (isVfsWithSuffix()) {
@@ -141,7 +143,7 @@ void ProcessDirectoryJob::process()
         const auto &e = f.second;
 
         PathTuple path;
-        path = _currentFolder.addName(e.nameOverride.isEmpty() ? f.first : e.nameOverride);
+        path = _currentFolder.addName(e.nameOverride.isEmpty() ? f.second.serverEntry.name : e.nameOverride);
 
         if (isVfsWithSuffix()) {
             // Without suffix vfs the paths would be good. But since the dbEntry and localEntry