fix: placeholder cover text, indexing timing, TOC long-press, cache deletion UI

- Fix fp4 fixed-point misuse in PlaceholderCoverGenerator (advanceX is 12.4
  fixed-point, not pixels) causing only first letter of each word to render
- Remove duplicate silentIndexNextChapterIfNeeded() call from loop() that
  blocked UI before render, preventing the indexing indicator from showing
- Fix indexing icon Y position to align within the status bar
- Add ignoreNextConfirmRelease to EpubReaderChapterSelectionActivity so
  long-press confirm release doesn't immediately select the first TOC item
- Reload recent books after cache deletion in HomeActivity and clear stale
  ignoreNextConfirmRelease flag to fix "no open books" and double-press bugs

Made-with: Cursor

lib/PlaceholderCover/PlaceholderCoverGenerator.cpp

@@ -1,6 +1,7 @@
 #include "PlaceholderCoverGenerator.h"
 
 #include <EpdFont.h>
+#include <EpdFontData.h>
 #include <HalStorage.h>
 #include <Logging.h>
 #include <Utf8.h>
@@ -170,7 +171,7 @@ class PixelBuffer {
       }
     }
 
-    return glyph->advanceX * scale;
+    return fp4::toPixel(glyph->advanceX) * scale;
   }
 
   /// Render a UTF-8 string at (x, y) where y is the top of the text line, with integer scaling.
@@ -232,7 +233,7 @@ int getCharAdvance(const EpdFontData* font, uint32_t cp) {
   const EpdFont fontObj(font);
   const EpdGlyph* glyph = fontObj.getGlyph(cp);
   if (!glyph) return 0;
-  return glyph->advanceX;
+  return fp4::toPixel(glyph->advanceX);
 }
 
 /// Split a string into words (splitting on whitespace: space, newline, tab, CR).