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/Serialization/Serialization.h

@@ -36,17 +36,23 @@ static void writeString(FsFile& file, const std::string& s) {
   file.write(reinterpret_cast<const uint8_t*>(s.data()), len);
 }
 
-static void readString(std::istream& is, std::string& s) {
+static constexpr uint32_t MAX_STRING_LENGTH = 4096;
+
+static bool readString(std::istream& is, std::string& s) {
   uint32_t len;
   readPod(is, len);
+  if (len > MAX_STRING_LENGTH) return false;
   s.resize(len);
   is.read(&s[0], len);
+  return true;
 }
 
-static void readString(FsFile& file, std::string& s) {
+static bool readString(FsFile& file, std::string& s) {
   uint32_t len;
   readPod(file, len);
+  if (len > MAX_STRING_LENGTH) return false;
   s.resize(len);
   file.read(&s[0], len);
+  return true;
 }
 }  // namespace serialization