chore: update cursor rulesets

.cursor/rules/documentation.mdc

@@ -0,0 +1,13 @@
+---
+alwaysApply: true
+---
+# Directive for Documentation Generation
+
+1. Produce a **small, focused set of documents** rather than an overwhelming volume.
+2. Ensure the content is **maintainable and worth preserving**, so that humans
+are motivated to keep it up to date.
+3. Prioritize **educational value**: the documents must clearly explain the
+workings of the system.
+4. Avoid **shallow, generic, or filler explanations** often found in
+AI-generated documentation.
+5. Aim for **clarity, depth, and usefulness**, so readers gain genuine understanding.