feat: upgrade platform and support webdav (#1047)

## Summary
- Upgrade platform from espressif32 6.12.0 (Arduino Core 2.0.17) to
pioarduino 55.03.37 (Arduino Core 3.3.7, ESP-IDF 5.5.2)
- Add WebDAV Class 1 server (RFC 4918) - SD card can be mounted as a
network drive
- I also slightly fixed the SDK and also made a [pull request
](https://github.com/open-x4-epaper/community-sdk/pull/21)

First PR #1030 (was closed because the implementation was based on an
old version of the libraries)
Issue #439

---------

Co-authored-by: Dave Allie <dave@daveallie.com>

src/network/WebDAVHandler.h

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <HalStorage.h>
+#include <WebServer.h>
+
+class WebDAVHandler : public RequestHandler {
+ public:
+  // RequestHandler interface
+  bool canHandle(WebServer& server, HTTPMethod method, const String& uri) override;
+  bool canRaw(WebServer& server, const String& uri) override;
+  void raw(WebServer& server, const String& uri, HTTPRaw& raw) override;
+  bool handle(WebServer& server, HTTPMethod method, const String& uri) override;
+
+ private:
+  // PUT streaming state (raw() is called in chunks)
+  FsFile _putFile;
+  String _putPath;
+  bool _putOk = false;
+  bool _putExisted = false;
+
+  // WebDAV method handlers
+  void handleOptions(WebServer& s);
+  void handlePropfind(WebServer& s);
+  void handleGet(WebServer& s);
+  void handleHead(WebServer& s);
+  void handlePut(WebServer& s);
+  void handleDelete(WebServer& s);
+  void handleMkcol(WebServer& s);
+  void handleMove(WebServer& s);
+  void handleCopy(WebServer& s);
+  void handleLock(WebServer& s);
+  void handleUnlock(WebServer& s);
+
+  // Utilities
+  String getRequestPath(WebServer& s) const;
+  String getDestinationPath(WebServer& s) const;
+  void urlEncodePath(const String& path, String& out) const;
+  bool isProtectedPath(const String& path) const;
+  int getDepth(WebServer& s) const;
+  bool getOverwrite(WebServer& s) const;
+  void clearEpubCacheIfNeeded(const String& path) const;
+  void sendPropEntry(WebServer& s, const String& href, bool isDir, size_t size, const String& lastModified) const;
+  String getMimeType(const String& path) const;
+};