add cursor rules directory

.cursor/rules/general.mdc

@@ -0,0 +1,9 @@
+---
+description: General rules always applicable across the project
+globs:
+alwaysApply: true
+---
+# Style
+
+- Comments must add value to code. Don't write filler comments explaining what you are doing next; they just add noise.
+- Add a comment to clarify surprising behavior which would not be obvious. Good variable naming and clear code organization is more important.