port: upstream PR #1342 - Book Info screen, richer metadata, safer controls

Ports upstream PR #1342 (feat: Add Book Info screen, richer metadata,
and safer file-browser controls) with mod-specific adaptations:

- Parse and cache series, seriesIndex, description from EPUB OPF
- Bump book.bin cache version to 6 for new metadata fields
- Add BookInfoActivity (new screen) accessible via Right button in FileBrowser
- Add ManageBook menu via Left button in FileBrowser (replaces upstream hidden delete)
- Guard all delete/archive actions with ConfirmationActivity (10 call sites)
- Add inputArmed gating to ConfirmationActivity to prevent accidental confirmation
- Safe deserialization: readString now returns bool with MAX_STRING_LENGTH guard
- Add series field to RecentBooksStore with JSON and binary serialization
- Add i18n keys: STR_BOOK_INFO, STR_AUTHOR, STR_SERIES, STR_FILE_SIZE, etc.

Made-with: Cursor

lib/Epub/Epub.cpp

@@ -78,6 +78,9 @@ bool Epub::parseContentOpf(BookMetadataCache::BookMetadata& bookMetadata) {
   bookMetadata.author = opfParser.author;
   bookMetadata.language = opfParser.language;
   bookMetadata.coverItemHref = opfParser.coverItemHref;
+  bookMetadata.series = opfParser.series;
+  bookMetadata.seriesIndex = opfParser.seriesIndex;
+  bookMetadata.description = opfParser.description;
 
   // Guide-based cover fallback: if no cover found via metadata/properties,
   // try extracting the image reference from the guide's cover page XHTML
@@ -517,6 +520,33 @@ const std::string& Epub::getLanguage() const {
   return bookMetadataCache->coreMetadata.language;
 }
 
+const std::string& Epub::getSeries() const {
+  static std::string blank;
+  if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
+    return blank;
+  }
+
+  return bookMetadataCache->coreMetadata.series;
+}
+
+const std::string& Epub::getSeriesIndex() const {
+  static std::string blank;
+  if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
+    return blank;
+  }
+
+  return bookMetadataCache->coreMetadata.seriesIndex;
+}
+
+const std::string& Epub::getDescription() const {
+  static std::string blank;
+  if (!bookMetadataCache || !bookMetadataCache->isLoaded()) {
+    return blank;
+  }
+
+  return bookMetadataCache->coreMetadata.description;
+}
+
 std::string Epub::getCoverBmpPath(bool cropped) const {
   const auto coverFileName = std::string("cover") + (cropped ? "_crop" : "");
   return cachePath + "/" + coverFileName + ".bmp";