feat: add turkish translation (#1192)

Description
  This Pull Request introduces Turkish language support to CrossPoint
  Reader firmware.


  Key Changes:
- Translation File: Added lib/I18n/translations/turkish.yaml with 315
translated
     string keys, covering all system UI elements.
- I18N Script Update: Modified scripts/gen_i18n.py to include the "TR"
     abbreviation mapping for Turkish.
- System Integration: Regenerated I18N C++ files to include the new
Language::TR
     enum and STRINGS_TR array.
- UI Availability: The language is now selectable in the Settings menu
and
     correctly handles Turkish-specific characters (ç, ğ, ı, ö, ş, ü).
- Documentation: Updated docs/i18n.md to include Turkish in the list of
     supported languages.

  Testing:
   - Verified the build locally with PlatformIO.
- Flashed the firmware to an Xteink X4 device and confirmed the Turkish
UI
     renders correctly.
---

### AI Usage

Did you use AI tools to help write this code?  Yes Gemini

---------

Co-authored-by: Baris Albayrak <baris@Bariss-MacBook-Pro.local>
Co-authored-by: Barış Albayrak <barisa@pop-os.lan>

docs/i18n.md

@@ -15,6 +15,7 @@ This guide explains the multi-language support system in CrossPoint Reader.
 - Ukrainian
 - Polish
 - Danish
+- Turkish
 
 ---