chore: add .gitattributes to enforce LF line endings

.gitattributes

@@ -0,0 +1,23 @@
+# Auto-detect text files and normalize line endings to LF (POSIX standard)
+* text=auto eol=lf
+
+# Explicitly ensure code and configuration files use LF
+*.py text eol=lf
+*.sh text eol=lf
+*.sql text eol=lf
+*.md text eol=lf
+*.yaml text eol=lf
+*.yml text eol=lf
+*.json text eol=lf
+*.txt text eol=lf
+.env.example text eol=lf
+.gitignore text eol=lf
+.gitattributes text eol=lf
+
+# Binary files
+*.png binary
+*.jpg binary
+*.jpeg binary
+*.gif binary
+*.ico binary
+*.tar.gz binary