fix(tasty): cleanup algorithm

Author: tenphi

src/tasty/injector/injector.ts

@@ -67,6 +67,14 @@ export class StyleInjector {
     if (generatedClass && registry.rules.has(generatedClass)) {
       const currentRefCount = registry.refCounts.get(generatedClass) || 0;
       registry.refCounts.set(generatedClass, currentRefCount + 1);
+      // If this class was previously marked as unused, clear that state now
+      if (registry.unusedRules.has(generatedClass)) {
+        registry.unusedRules.delete(generatedClass);
+        if (registry.metrics) {
+          // Consider this a reuse rather than a cold miss
+          registry.metrics.unusedHits++;
+        }
+      }
 
       // Update metrics
       if (registry.metrics) {

src/tasty/injector/sheet-manager.ts

@@ -575,6 +575,25 @@ export class SheetManager {
       rulesInSheet.sort((a, b) => b.ruleInfo.ruleIndex - a.ruleInfo.ruleIndex);
 
       for (const { className, ruleInfo } of rulesInSheet) {
+        // SAFETY: Re-check that the rule is still unused at deletion time.
+        // Between scheduling and execution a class may have been restored
+        // (refCounts set and removed from unusedRules). Skip such entries.
+        if (!registry.unusedRules.has(className)) {
+          continue;
+        }
+        if (registry.refCounts.has(className)) {
+          // Class became active again; do not delete
+          continue;
+        }
+
+        // Ensure we delete the same RuleInfo we marked earlier to avoid
+        // accidentally deleting updated rules for the same class.
+        const currentInfo = registry.rules.get(className);
+        if (currentInfo && currentInfo !== ruleInfo) {
+          // Rule was replaced; skip deletion of the old reference
+          continue;
+        }
+
         this.deleteRule(registry, ruleInfo);
         registry.rules.delete(className);
         registry.unusedRules.delete(className);

src/tasty/styles/transition.ts

@@ -27,6 +27,7 @@ const MAP = {
     'border',
     'border-radius',
     'outline',
+    'opacity',
   ],
   inset: ['box-shadow'],
   mark: ['box-shadow'],