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

src/css-rules/no-empty-blocks/empty-nested-style-processor.ts

@@ -7,11 +7,11 @@ import { areAllChildrenEmpty, getStyleKeyName } from './property-utils.js';
 /**
  * Processes nested style objects like selectors and media queries.
  */
-export function processEmptyNestedStyles(
+export const processEmptyNestedStyles = (
   ruleContext: Rule.RuleContext,
   node: TSESTree.ObjectExpression,
   reportedNodes: Set<TSESTree.Node>,
-): void {
+): void => {
   node.properties.forEach((property) => {
     if (property.type !== 'Property') {
       return;
@@ -72,4 +72,4 @@ export function processEmptyNestedStyles(
       });
     }
   });
-}
+};