Add Korean translation

[MerciHanrim]

Adds Korean (ko) localization for all three YACReader components,
based on the develop branch source files (YACReader 10.0.0).

Files added

• YACReader/yacreader_ko.ts
• YACReaderLibrary/yacreaderlibrary_ko.ts
• YACReaderLibraryServer/yacreaderlibraryserver_ko.ts
  (newly added — no Korean translation existed previously)

Status

• yacreaderlibrary_ko.ts: 699 strings, 100% finished
• yacreaderlibraryserver_ko.ts: 25 strings, 100% finished
• yacreader_ko.ts mirrors yacreaderlibrary source content (679
  strings, identical in develop)

All .qm files have been compiled locally and verified to apply
correctly throughout YACReader, YACReaderLibrary, and
YACReaderLibraryServer on Windows.

This follows up on the email correspondence regarding the Korean
localization completion.

[luisangelsm]

I need to fix the translation files, sorry for the mess, all the strings are in all the files and that's completely wrong. I'll get back to you once I fix everything.

[luisangelsm]

@MerciHanrim I updated the translation files, now each file only has the strings for its app. There are a few new strings in yacreader_ko.ts for YACReader 10.1 in case you want to translate them before merging the PR.

[MerciHanrim]

@luisangelsm I've translated the new strings for YACReader 10.1 in
both yacreader_ko.ts and yacreaderlibrary_ko.ts. The PR should be
ready to merge now. Thank you for splitting the translation files
properly!