Add FlatProgressBar — canvas-rendered cross-platform progress bar

Replaces TProgressBar in TWisdomProgressDialog with TFlatProgressBar,
drawn entirely via Canvas (plain rectangle, no native widget styling).
Dialog now receives the active TAppTheme so both dark and light themes
are applied consistently to background, label, and progress bar.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ewsdr.lpi

@@ -159,6 +159,10 @@
         <Filename Value="FlatRadioButton.pas"/>
         <IsPartOfProject Value="True"/>
       </Unit>
+      <Unit>
+        <Filename Value="FlatProgressBar.pas"/>
+        <IsPartOfProject Value="True"/>
+      </Unit>
       <Unit>
         <Filename Value="EqualizerControl.pas"/>
         <IsPartOfProject Value="True"/>