fix(release): force C locale for RFC 822 pubDate; clean up appcast layout

The first release.sh run wrote a Chinese-locale pubDate ("一, 27 4月 2026 …")
into appcast.xml, which Sparkle's RFC 822 date parser rejects. Force
LC_ALL=C around the date call so future releases produce the standard
"Mon, 27 Apr 2026 11:02:01 +0000" format. Manually fix the v1.0.02
entry's pubDate and move <language> back above <item> for a tidy feed.

appcast.xml

@@ -4,10 +4,11 @@
         <title>OpenLess</title>
         <link>https://raw.githubusercontent.com/appergb/openless/main/appcast.xml</link>
         <description>OpenLess update feed</description>
+        <language>zh-CN</language>
 
         <item>
             <title>OpenLess 1.0.02</title>
-            <pubDate>一, 27  4月 2026 11:02:01 +0000</pubDate>
+            <pubDate>Mon, 27 Apr 2026 11:02:01 +0000</pubDate>
             <sparkle:version>A1004</sparkle:version>
             <sparkle:shortVersionString>1.0.02</sparkle:shortVersionString>
             <sparkle:minimumSystemVersion>15.0</sparkle:minimumSystemVersion>
@@ -47,6 +48,5 @@ xattr -dr com.apple.quarantine /Applications/OpenLess.app
                 type="application/octet-stream"
                 sparkle:edSignature="PVtUgUO28Re0Q80VbF3r6NCamZMgW+X7DANqwOD97yiT2rly9J2MmPt0xnaRj6fWieKsgHUZZ94C8RalkwVQAA==" />
         </item>
-        <language>zh-CN</language>
     </channel>
 </rss>

scripts/release.sh

@@ -83,7 +83,7 @@ else
   NOTES_HTML="<![CDATA[<p>OpenLess ${VERSION}</p>]]>"
 fi
 
-PUB_DATE=$(/bin/date -u +"%a, %d %b %Y %H:%M:%S +0000")
+PUB_DATE=$(LC_ALL=C /bin/date -u +"%a, %d %b %Y %H:%M:%S +0000")
 DOWNLOAD_URL="https://github.com/appergb/openless/releases/download/v${VERSION}/${ZIP_NAME}"
 
 # 7. 在 appcast.xml 的标记行后插入新 <item>