feat(topic-update-manifest): add definition for the packages-v2 amendment

Author: MingcongBai

content/developer/packaging/topic-update-manifest.md

@@ -59,6 +59,23 @@ topics = [
 ]
 ```
 
+Amendment: packages-v2
+---
+
+{% card(type="success") %}
+This amendment has not been deployed yet - we will update the main text to reflect its replacement for `packages` following its deployment.
+此规范更新目前尚未实装；实装后将并入规范正文。
+{% end %}
+
+In August 2025, we introduced the `[packages-v2]` section to help marking version ranges for important (and especially security) updates. The version range compares with the package version *before* the update, resolving an issue where, if the user happens to have missed the exact version defined in the metadata, they would never be prompted about the updates (in oma and potentially other package management frontends).
+
+```toml
+[packages-v2]
+firefox = "<= 142"
+thunderbird = ">= 108 && < 142"
+seamonkey = "141 || 142 || 143"
+```
+
 Files
 ===
 

content/developer/packaging/topic-update-manifest.zh.md

@@ -1,5 +1,5 @@
 +++
-title = "更新主题元数据"
+title = "更新主题元数据规范"
 description = "安同 OS 更新元数据规范"
 +++
 
@@ -56,6 +56,22 @@ topics = [
 ]
 ```
 
+规范更新：packages-v2
+---
+
+{% card(type="success") %}
+此规范更新目前尚未实装；实装后将并入规范正文。
+{% end %}
+
+2025 年 8 月，我们引入了 `[packages-v2]` 字段，以便定义重要更新（尤其是安全更新）波及的软件包范围，并以更新前的软件包作为对比基准，解决用户因错过特定版本软件包更新而在 oma 等包管理前端中收不到更新公告的问题。该字段的写入样例如下：
+
+```toml
+[packages-v2]
+firefox = "<= 142"
+thunderbird = ">= 108 && < 142"
+seamonkey = "141 || 142 || 143"
+```
+
 文件存放
 ===