feat 🥁: add no-zero-unit rule

This rule enforces unitless zero values in vanilla-extract style objects:
- Automatically removes unnecessary units from zero values
- Handles both positive and negative zero values
- Preserves units where required (time properties, CSS functions)
- Works with all vanilla-extract APIs

.gitignore

@@ -30,3 +30,6 @@ pnpm-debug.log*
 
 # typescript
 *.tsbuildinfo
+
+# dev helper
+src/css-sample/