translation(ko): improve Korean config_ko.xml translation quality (doxygen#12147)

* translation: fix Korean spelling 디렉토리 → 디렉터리 in config_ko.xml

Replace all occurrences of the non-standard spelling '디렉토리'
with the standard Korean spelling '디렉터리' (directory).

This affects 56 occurrences throughout the file covering all
configuration option groups.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Co-authored-by: doxygen <1300762+doxygen@users.noreply.github.com>

* translation: improve Korean config translation quality

- Replace non-standard '디렉토리' with standard '디렉터리' (56 occurrences)
  per the National Institute of Korean Language spelling standard
- Fix grammatical error in PROJECT_ICON: '문서가 볼 때' → '문서를 표시할 때'
- Replace awkward calque in PROJECT_BRIEF: '빠른 아이디어를 제공합니다'
  → '간략히 전달합니다'
- Replace odd technical calque in OUTPUT_LANGUAGE: '상수 출력'
  → '고정 문자열 출력'

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Co-authored-by: doxygen <1300762+doxygen@users.noreply.github.com>

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: doxygen <1300762+doxygen@users.noreply.github.com>

Author: Copilot