Add .gitattributes for line endings

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitattributes

@@ -0,0 +1,16 @@
+# Normalize text files to LF in the repo
+* text=auto
+
+# Shell scripts must keep LF so they run on Linux/macOS/Termux
+gradlew text eol=lf
+*.sh text eol=lf
+
+# Windows batch files need CRLF
+*.bat text eol=crlf
+*.cmd text eol=crlf
+
+# Binaries
+*.jar binary
+*.png binary
+*.jpg binary
+*.webp binary