fix: address PR review comments

- Replace hard-coded Chinese string with R.string.acc_back in BaseToolBar.java
- Remove reference to non-existent GitHub build variant in SIGNING.md
- Add missing semicolon in v2er.css

Fixes review comments from Copilot PR review.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: graycreate

SIGNING.md

@@ -52,5 +52,4 @@ If you need to test release builds locally:
 - Never commit keystore files to the repository
 - Always clean up temporary keystore files after use
 - The `.gitignore` file excludes all `.jks` and `.keystore` files
-- For production releases, always use the GitHub Actions release pipeline
-- The GitHub build variant now uses debug signing for simplicity
+- For production releases, always use the GitHub Actions release pipeline

app/src/main/assets/html/v2er.css

@@ -29,7 +29,7 @@ img {
 
 .dark .topic_content{
     background:#111214;
-    color: rgba(255,255,255, 0.9)
+    color: rgba(255,255,255, 0.9);
 }
 
 div.subtle {

app/src/main/java/me/ghui/v2er/widget/BaseToolBar.java

@@ -37,7 +37,7 @@ private void init() {
         setContentInsetEndWithActions(0);
         setNavigationIcon(R.drawable.ic_arrow_back_black);
         getNavigationIcon().setTint(Theme.getColor(R.attr.icon_tint_color, getContext()));
-        setNavigationContentDescription("返回");
+        setNavigationContentDescription(R.string.acc_back);
     }
 
     @Override