chore: add .gitignore for build artifacts and docs

Add .gitignore to exclude build artifacts (binaries, object files) and internal documentation from version control. Clean build verification confirms all features working correctly.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: otonomee

.gitignore

@@ -0,0 +1,12 @@
+# Build artifacts
+*.o
+*.hi
+mips-converter
+mips-converter-test
+main.exe
+
+# Documentation (Claude Code internal)
+docs/
+
+# macOS
+.DS_Store