Add bilingual support (English/Greek) with live language switching

[YatesMold]

Added Greek translation support using Qt Linguist (tr(), .ts/.qm).
Language switcher in the status bar, choice saved across sessions via QSettings.

Key changes:

• Decoupled university/department display labels from logic keys using Qt::UserRole so that translation never affects resource paths or control flow comparisons
• Replaced English prefix matching on status messages with a dedicated status_update signal, removing the dependency on untranslated string content
• Wrapped all user-facing strings in tr() using .arg() for proper sentence structure in both languages
• Added qt_add_translations to CMake with LinguistTools, fixed stale resources.qrc path (resources/ -> include/resources/)
• Added applyTranslator() helper for clean QTranslator install/remove
• Added retranslate() and changeEvent() for live UI refresh on language switch
• Greek translations provided for all UI strings, university and department names

Fixes #16

[TolisSth]

Run cmake -B build
-- The CXX compiler identification is GNU 13.3.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Success
-- Found Threads: TRUE
-- Performing Test HAVE_STDATOMIC
-- Performing Test HAVE_STDATOMIC - Success
-- Found WrapAtomic: TRUE
-- Found OpenGL: /usr/lib/x86_64-linux-gnu/libOpenGL.so
-- Found WrapOpenGL: TRUE
-- Could NOT find XKB (missing: XKB_LIBRARY XKB_INCLUDE_DIR) (Required is at least version "0.5.0")
-- Found WrapVulkanHeaders: /usr/include
-- Could NOT find Qt6LinguistTools (missing: Qt6LinguistTools_DIR)
CMake Error at CMakeLists.txt:7 (find_package):
  Found package configuration file:

    /usr/lib/x86_64-linux-gnu/cmake/Qt6/Qt6Config.cmake

  but it set Qt6_FOUND to FALSE so package "Qt6" is considered to be NOT
  FOUND.  Reason given by package:

  Failed to find required Qt component "LinguistTools".

  Expected Config file at
  "/usr/lib/x86_64-linux-gnu/cmake/Qt6LinguistTools/Qt6LinguistToolsConfig.cmake"
  does NOT exist



  Configuring with --debug-find-pkg=Qt6LinguistTools might reveal details why
  the package was not found.

  Configuring with -DQT_DEBUG_FIND_PACKAGE=ON will print the values of some
  of the path variables that find_package uses to try and find the package.



-- Configuring incomplete, errors occurred!
Error: Process completed with exit code 1.

This shows up, I suggest you take a look at your CMake or run the command as instructed by cppcheck

[YatesMold]

Το σφάλμα δεν είναι στο CMake. Το qt6-tools-dev δεν εγκαθίσταται αυτόματα
στο Debian/Ubuntu. Το έχω προσθέσει στο README, το build θα δουλέψει μετά από:

sudo apt install build-essential cmake qt6-base-dev qt6-tools-dev qt6-tools-dev-tools policykit-1

[TolisSth]

You should go ahead and add that in the build.yml so we can get the .deb file right from the CI pipeline

[michadasis]

For arch?

[YatesMold]

Έχω προσθέσει το qt6-tools-dev στο build.yml και διόρθωσα και το path του icon.

[YatesMold]

Για Arch, το qt6-tools που αναφέρεται ήδη στο README περιλαμβάνει τα απαραίτητα, οπότε δεν χρειάζεται αλλαγή εκεί.

[michadasis]

Είσαι σίγουρος ότι το path του icon ήταν λανθασμένο;

[michadasis]

Για επόμενα pull requests να ξέρεις οτι θα ηταν καλύτερο να χωρίζονται τα fixes, αλλα αυτη τη φορα δεν πειράζει, εκτιμάμαι πολυ την συμμετοχή σου

[YatesMold]

Έγινε κατά λάθος. Βασίστηκα στο output του find που έδειξε ./include/resources/resources.qrc και υπέθεσα ότι ήταν ήδη εκεί.
Θέλετε να το κάνω revert στο αρχικό path;
Και ευχαριστώ για την παρατήρηση, θα το έχω υπόψη για τα επόμενα PR!

[michadasis]

Αμα μπορείς ναι

[YatesMold]

Έγινε, το resources επέστρεψε στη ρίζα του project.

[TolisSth]

Seems fine, hope it doesn't crash the CI pipeline

[michadasis]

build.yml remains unchanges with only a minor dependency addition, code seems to be working, looks pretty okay to me