release: update appcast for v1.8.0

Author: JerryZLiu

docs/appcast.xml

@@ -3,6 +3,18 @@
   <channel>
     <title>Dayflow Updates</title>
     <language>en</language>
+    <item>
+      <title>Version 1.8.0</title>
+      <pubDate>Tue, 24 Feb 2026 08:24:15 +0000</pubDate>
+      <enclosure url="https://github.com/JerryZLiu/Dayflow/releases/download/v1.8.0/Dayflow.dmg"
+                 sparkle:version="91"
+                 sparkle:shortVersionString="1.8.0"
+                 length="37027269"
+                 type="application/octet-stream"
+                 sparkle:edSignature="19Y8bWIGi8ZE9wNZNy8i5EwrbqjZTrdwRtd+q1mfOiCkN8Als9iFoTP/gU67ElI7/ji+WQE3cWvngIeAFDR7Dw=="/>
+      <sparkle:minimumSystemVersion>13.0</sparkle:minimumSystemVersion>
+      <releaseNotesLink>https://github.com/JerryZLiu/Dayflow/releases/tag/v1.8.0</releaseNotesLink>
+    </item>
     <item>
       <title>Version 1.7.0</title>
       <pubDate>Fri, 06 Feb 2026 20:35:00 +0000</pubDate>