docs(changelog): distill release notes and add platform grouping

The v2.5.4 notes had grown to 97 free-form entries exposed verbatim in
the in-app update dialog. Distill them to 58 one-theme-per-line entries
capped at ~60 CJK characters with no internal terminology, and move the
writing rules into template/Changelog.md so every cycle starts from them.

Release plumbing now agrees on the --- divider: extract_update_logs.sh
stops there like updatelog.mjs, so file-only content never reaches
release bodies, while updater.mjs appends a per-tag See More link to the
update notes it generates. scripts-workflow/group_platforms.sh locks
platform entries under emoji platform headings, wired into pre-commit,
release and autobuild CI, and the changelog bump script; AGENTS.md points
agents at the template rules.

scripts/extract_update_logs.sh

@@ -13,12 +13,17 @@ if [[ ! -f "$CHANGELOG_FILE" ]]; then
   exit 1
 fi
 
-# 提取从第一个 '## v' 开始到下一个 '## v' 前的内容
+# 提取从第一个 '## v' 开始到 '---' 或下一个 '## v' 前的内容
+# '---' 与 scripts/updatelog.mjs 的解析一致：分隔线之后的内容
+# 只属于仓库文件，不进入任何 release body
 UPDATE_LOGS=$(awk '
   /^## v/ {
     if (found) exit;
     found=1
   }
+  /^---/ && found {
+    exit
+  }
   found
 ' "$CHANGELOG_FILE")
 

scripts/updater.mjs

@@ -72,11 +72,14 @@ async function processRelease(github, options, tag, isAlpha) {
       tag: tag.name,
     })
 
+    const notes = await resolveUpdateLog(tag.name).catch(() =>
+      resolveUpdateLogDefault().catch(() => 'No changelog available'),
+    )
+    const releaseUrl = `https://github.com/${options.owner}/${options.repo}/releases/tag/${tag.name}`
+
     const updateData = {
       name: tag.name,
-      notes: await resolveUpdateLog(tag.name).catch(() =>
-        resolveUpdateLogDefault().catch(() => 'No changelog available'),
-      ),
+      notes: `${notes}\n\n**[See More](${releaseUrl})**`,
       pub_date: new Date().toISOString(),
       platforms: {
         // platform format: