chore: normalize line endings to LF

.gitattributes

@@ -0,0 +1,19 @@
+# Normalize line endings to LF across the repo.
+# Prevents CRLF/LF churn in PR diffs.
+* text=auto eol=lf
+
+# Explicit text types
+*.py    text eol=lf
+*.sql   text eol=lf
+*.md    text eol=lf
+*.toml  text eol=lf
+*.yaml  text eol=lf
+*.yml   text eol=lf
+*.json  text eol=lf
+*.sh    text eol=lf
+*.service text eol=lf
+
+# Binary types
+*.pyc   binary
+*.db    binary
+*.key   binary