fix(i18n): M104 折叠条标签的中文改成「助手」，别让 AgentStripLabel 两套译文相同

chinese_catalog_is_actually_chinese 抓到的（en == zh 就是漏译）：`("AI", "AI")` 在 48px 折叠条上
两边都能排下，但中文表里塞一条与英文逐字相同的条目等于漏译。中文用「助手」（12px 下 24px 宽，条上放得下）。

crates/i18n/src/catalog/agent.rs

@@ -19,7 +19,7 @@ macro_rules! agent_entries {
             AgentDetach => ("Pop out", "拆出"),
             AgentDock => ("Dock back", "收回"),
             AgentOpen => ("Open assistant", "打开助手"),
-            AgentStripLabel => ("AI", "AI"),
+            AgentStripLabel => ("AI", "助手"),
             AgentSend => ("Send", "发送"),
             AgentStop => ("Stop", "中断"),
             AgentPlaceholder => ("Message the assistant…", "给助手发消息…"),

crates/i18n/src/catalog/golden.rs

@@ -100,7 +100,7 @@ pub(super) const GOLDEN: &[(&str, &str, &str)] = &[
     ("AgentDetach", "Pop out", "拆出"),
     ("AgentDock", "Dock back", "收回"),
     ("AgentOpen", "Open assistant", "打开助手"),
-    ("AgentStripLabel", "AI", "AI"),
+    ("AgentStripLabel", "AI", "助手"),
     ("AgentSend", "Send", "发送"),
     ("AgentStop", "Stop", "中断"),
     ("AgentPlaceholder", "Message the assistant…", "给助手发消息…"),