fix(l10n): em-dash sweep across EN source and translations, backfill Crowdin gap

- HellionStrings.resx: 10 in-prose em-dashes -> period/colon per style guide
- 18 HellionStrings.<lang>.resx: 114 mechanical em-dash edits via heuristic
    (period before capital, colon otherwise). Skipped: fr (already clean),
    zh-Hans/zh-Hant (already clean), ru/uk (em-dash is orthographic norm)
- HellionStrings.de.resx: fix substantive-heuristic miss in Wizard_Cancel_Label
- Language.de.resx: add Hellion Forge maintainer header (native-maintained)
- Backfill the 4 post-Crowdin keys (Options_ColorSelectedInputChannelButton_*,
    Options_HideInNewGamePlusMenu_*) into 13 legacy Crowdin locales with
    per-key AI-assisted comment marker. All 23 Language.*.resx now at 456 keys.

HellionChat/Resources/Language.zh-Hans.resx

@@ -1466,4 +1466,20 @@ Your old database can still be recovered, please contact the plugin author for h
   <data name="ChatExport_Initial" xml:space="preserve">
         <value>Loading logs ...</value>
     </data>
+  <data name="Options_ColorSelectedInputChannelButton_Name" xml:space="preserve">
+    <value>用频道颜色为频道选择器染色</value>
+    <comment>AI-assisted machine translation. Pending native-speaker review.</comment>
+  </data>
+  <data name="Options_ColorSelectedInputChannelButton_Description" xml:space="preserve">
+    <value>输入框旁边的频道选择器按钮将以当前活动频道的颜色着色。与输入文本本身的着色相匹配。</value>
+    <comment>AI-assisted machine translation. Pending native-speaker review.</comment>
+  </data>
+  <data name="Options_HideInNewGamePlusMenu_Name" xml:space="preserve">
+    <value>在新游戏+菜单打开时隐藏</value>
+    <comment>AI-assisted machine translation. Pending native-speaker review.</comment>
+  </data>
+  <data name="Options_HideInNewGamePlusMenu_Description" xml:space="preserve">
+    <value>在新游戏+菜单打开时隐藏聊天。关闭菜单时聊天会再次显示。</value>
+    <comment>AI-assisted machine translation. Pending native-speaker review.</comment>
+  </data>
 </root>