Console: Fix theme selection

apps/routerconsole/java/src/net/i2p/router/web/CSSHelper.java

@@ -21,6 +21,7 @@ public class CSSHelper extends HelperBase {
     /**  @since 0.9.33 moved from ConfigUIHelper */
     public static final String PROP_THEME_PFX = PROP_THEME_NAME + '.';
     public static final String DEFAULT_THEME = "light";
+    public static final String ALT_THEME = "dark";
     public static final String BASE_THEME_PATH = "/themes/console/";
     private static final String FORCE = "classic";
     public static final String PROP_REFRESH = "routerconsole.summaryRefresh";

apps/routerconsole/java/src/net/i2p/router/web/helpers/ConfigUIHelper.java

@@ -76,6 +76,7 @@ public class ConfigUIHelper extends HelperBase {
          Set<String> rv = new TreeSet<String>();
          // add a failsafe even if we can't find any themes
          rv.add(CSSHelper.DEFAULT_THEME);
+         rv.add(CSSHelper.ALT_THEME);
          File dir = new File(_context.getBaseDir(), "docs/themes/console");
          File[] files = dir.listFiles();
          if (files == null)