feat: keep only last 2 hours of search history

- Filter history to show only items from last 2 hours
- Pinned items are always kept regardless of age
- Auto-cleanup old unpinned items from database
- Increased fetch limit to 50 to ensure enough items for filtering

src/composables/useSearchHistory.ts

@@ -15,12 +15,25 @@ export interface HistoryItem {
 export function useSearchHistory() {
   const history = ref<HistoryItem[]>([])
   const loading = ref(false)
+  const HISTORY_HOURS = 2 // Keep last 2 hours of history
 
   async function loadHistory() {
     loading.value = true
     try {
-      const result = await apiCall('get_search_history', { limit: 30 })
-      history.value = Array.isArray(result) ? result : []
+      const result = await apiCall('get_search_history', { limit: 50 })
+      const allHistory = Array.isArray(result) ? result : []
+      
+      // Filter to last 2 hours (keep pinned items regardless of age)
+      const cutoffTime = Date.now() - (HISTORY_HOURS * 60 * 60 * 1000)
+      history.value = allHistory.filter((item: HistoryItem) => {
+        if (item.pinned) return true // Always keep pinned items
+        if (!item.updated_at) return false
+        const itemTime = new Date(item.updated_at).getTime()
+        return itemTime >= cutoffTime
+      })
+      
+      // Clean up old unpinned items from database
+      cleanupOldHistory(cutoffTime)
     } catch (e) {
       console.error('Failed to load history:', e)
     } finally {
@@ -28,6 +41,23 @@ export function useSearchHistory() {
     }
   }
 
+  async function cleanupOldHistory(cutoffTime: number) {
+    try {
+      const result = await apiCall('get_search_history', { limit: 100 })
+      const allHistory = Array.isArray(result) ? result : []
+      for (const item of allHistory) {
+        if (item.pinned) continue
+        if (!item.updated_at) continue
+        const itemTime = new Date(item.updated_at).getTime()
+        if (itemTime < cutoffTime) {
+          await apiCall('delete_search_history', { id: item.id })
+        }
+      }
+    } catch (e) {
+      console.error('Failed to cleanup old history:', e)
+    }
+  }
+
   async function saveToHistory(query: string, chatState: string, mode: string) {
     const id = `h_${Date.now()}_${Math.random().toString(36).slice(2, 8)}`
     try {