refactor(ci): use marker comments instead of regex for tracker workflow

Add TRACKER: HTML comment markers to COMPATIBILITY.md, README.md, and
all 5 translation READMEs. Rewrite gitea-tracker.yml to use grep -n
for precise line-based insertion and sed line-address editing.

Markers introduced:
- TRACKER:QUICK-REF-MAX  — Quick Reference max tested version
- TRACKER:VERSION-INSERT — Version History row insertion point
- TRACKER:LATEST-VERIFIED — latest verified note version
- TRACKER:BADGE — shields.io badge version
- TRACKER:LATEST-TESTED — latest tested version in READMEs

Co-Authored-By: Claude <noreply@anthropic.com>

docs/README.ko.md

@@ -58,7 +58,7 @@ cd tools && go run . dev
 ## 호환성
 
 - **Gitea 1.25+** — v1.25에서 도입된 메일 템플릿 디렉토리 구조 사용
-- **최신 테스트:** Gitea 1.26.4
+- **최신 테스트:** Gitea 1.26.4<!-- TRACKER:LATEST-TESTED -->
 - Gitea 공식 템플릿과 100% 호환 — 자세한 내용은 [COMPATIBILITY.md](../COMPATIBILITY.md) 참조
 
 ## 라이선스