feat: add highlights filter button to reading progress filters

- Add 'highlighted' filter type to ReadingProgressFilterType
- New filter button with yellow highlighter icon
- Filter shows only articles that have highlights
- Highlights filter checks both eventReference and urlReference tags
- Color-coded: green for completed, yellow for highlighted, blue for others
- Applies to reads and links tabs in /me page

src/utils/readingProgressUtils.ts

@@ -1,16 +1,35 @@
 import { ReadItem } from '../services/readsService'
 import { ReadingProgressFilterType } from '../components/ReadingProgressFilters'
+import { Highlight } from '../types/highlights'
 
 /**
  * Filters ReadItems by reading progress
  */
 export function filterByReadingProgress(
   items: ReadItem[],
-  filter: ReadingProgressFilterType
+  filter: ReadingProgressFilterType,
+  highlights?: Highlight[]
 ): ReadItem[] {
+  // Build a map of article references to highlight count
+  const articleHighlightCount = new Map<string, number>()
+  if (highlights) {
+    highlights.forEach(h => {
+      if (h.eventReference) {
+        const count = articleHighlightCount.get(h.eventReference) || 0
+        articleHighlightCount.set(h.eventReference, count + 1)
+      }
+      if (h.urlReference) {
+        const count = articleHighlightCount.get(h.urlReference) || 0
+        articleHighlightCount.set(h.urlReference, count + 1)
+      }
+    })
+  }
+
   return items.filter((item) => {
     const progress = item.readingProgress || 0
     const isMarked = item.markedAsRead || false
+    const hasHighlights = (articleHighlightCount.get(item.id) || 0) > 0 || 
+                         (item.url && (articleHighlightCount.get(item.url) || 0) > 0)
     
     switch (filter) {
       case 'unopened':
@@ -21,6 +40,8 @@ export function filterByReadingProgress(
         return progress > 0.10 && progress <= 0.94 && !isMarked
       case 'completed':
         return progress >= 0.95 || isMarked
+      case 'highlighted':
+        return hasHighlights
       case 'all':
       default:
         return true