feat(ui): change popup logic (#442)

## Summary

* refactors Indexing popups into ScreenComponents (they had different
implementations in different files)
* removes Indexing popup for small chapters
* only show Indexing popup (without progress bar) for large chapters
(using same minimum file size condition as for progress bar before)

## Additional Context

* Having to show even single popup message and redraw the screen slows
down the flow significantly
* Testing results:
    * Opening large chapter with progress bar - 11 seconds
* Same chapter without progress bar, only single Indexing popup - 5
seconds

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### AI Usage

Did you use AI tools to help write this code? _**< PARTIALLY>**_

lib/Epub/Epub/parsers/ChapterHtmlSlimParser.h

@@ -18,7 +18,7 @@ class ChapterHtmlSlimParser {
   const std::string& filepath;
   GfxRenderer& renderer;
   std::function<void(std::unique_ptr<Page>)> completePageFn;
-  std::function<void(int)> progressFn;  // Progress callback (0-100)
+  std::function<void()> popupFn;  // Popup callback
   int depth = 0;
   int skipUntilDepth = INT_MAX;
   int boldUntilDepth = INT_MAX;
@@ -52,7 +52,7 @@ class ChapterHtmlSlimParser {
                                  const uint8_t paragraphAlignment, const uint16_t viewportWidth,
                                  const uint16_t viewportHeight, const bool hyphenationEnabled,
                                  const std::function<void(std::unique_ptr<Page>)>& completePageFn,
-                                 const std::function<void(int)>& progressFn = nullptr)
+                                 const std::function<void()>& popupFn = nullptr)
       : filepath(filepath),
         renderer(renderer),
         fontId(fontId),
@@ -63,7 +63,7 @@ class ChapterHtmlSlimParser {
         viewportHeight(viewportHeight),
         hyphenationEnabled(hyphenationEnabled),
         completePageFn(completePageFn),
-        progressFn(progressFn) {}
+        popupFn(popupFn) {}
   ~ChapterHtmlSlimParser() = default;
   bool parseAndBuildPages();
   void addLineToPage(std::shared_ptr<TextBlock> line);