Add .gitattributes to enforce LF line endings

.gitattributes

@@ -0,0 +1,18 @@
+# Normalize line endings to LF for all text files
+* text=auto eol=lf
+
+# Explicitly handle markdown
+*.md text eol=lf
+
+# Explicitly handle config files
+*.yml text eol=lf
+*.yaml text eol=lf
+*.json text eol=lf
+*.toml text eol=lf
+
+# Binary files — don't touch
+*.png binary
+*.jpg binary
+*.jpeg binary
+*.gif binary
+*.pdf binary