feat : add getExportUrl to time-entries service and i18n key

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/services/time-entries.ts

@@ -50,5 +50,23 @@ export function useTimeEntryService() {
         })
     }
 
-    return { getByDateRange, getActive, create, update, remove }
+    function getExportUrl(params: {
+        after: string
+        before: string
+        user?: number
+        project?: number
+        tags?: number[]
+    }): string {
+        const query = new URLSearchParams()
+        query.set('after', params.after)
+        query.set('before', params.before)
+        if (params.user) query.set('user', String(params.user))
+        if (params.project) query.set('project', String(params.project))
+        if (params.tags?.length) {
+            params.tags.forEach(id => query.append('tags[]', String(id)))
+        }
+        return `/api/time_entries/export?${query.toString()}`
+    }
+
+    return { getByDateRange, getActive, create, update, remove, getExportUrl }
 }