Adds margin setting and calibre web

Also made the menu items dynamic and capital case. Looks better from a design perspective but I suppose this is an optional thing to accept

lib/OpdsParser/OpdsParser.h

@@ -0,0 +1,77 @@
+#pragma once
+#include <expat.h>
+
+#include <string>
+#include <vector>
+
+/**
+ * Represents a book entry from an OPDS feed.
+ */
+struct OpdsBook {
+  std::string title;
+  std::string author;
+  std::string epubUrl;  // Relative URL like "/books/get/epub/3/Calibre_Library"
+  std::string id;
+};
+
+/**
+ * Parser for OPDS (Open Publication Distribution System) Atom feeds.
+ * Uses the Expat XML parser to parse OPDS catalog entries.
+ *
+ * Usage:
+ *   OpdsParser parser;
+ *   if (parser.parse(xmlData, xmlLength)) {
+ *     for (const auto& book : parser.getBooks()) {
+ *       // Process book entries
+ *     }
+ *   }
+ */
+class OpdsParser {
+ public:
+  OpdsParser() = default;
+  ~OpdsParser();
+
+  // Disable copy
+  OpdsParser(const OpdsParser&) = delete;
+  OpdsParser& operator=(const OpdsParser&) = delete;
+
+  /**
+   * Parse an OPDS XML feed.
+   * @param xmlData Pointer to the XML data
+   * @param length Length of the XML data
+   * @return true if parsing succeeded, false on error
+   */
+  bool parse(const char* xmlData, size_t length);
+
+  /**
+   * Get the parsed books.
+   * @return Vector of OpdsBook entries
+   */
+  const std::vector<OpdsBook>& getBooks() const { return books; }
+
+  /**
+   * Clear all parsed books.
+   */
+  void clear();
+
+ private:
+  // Expat callbacks
+  static void XMLCALL startElement(void* userData, const XML_Char* name, const XML_Char** atts);
+  static void XMLCALL endElement(void* userData, const XML_Char* name);
+  static void XMLCALL characterData(void* userData, const XML_Char* s, int len);
+
+  // Helper to find attribute value
+  static const char* findAttribute(const XML_Char** atts, const char* name);
+
+  XML_Parser parser = nullptr;
+  std::vector<OpdsBook> books;
+  OpdsBook currentBook;
+  std::string currentText;
+
+  // Parser state
+  bool inEntry = false;
+  bool inTitle = false;
+  bool inAuthor = false;
+  bool inAuthorName = false;
+  bool inId = false;
+};