mcp_dart 2.4.1

mcp_dart 2.4.1 restores Dart 3.13 package-analysis compatibility and hardens
Streamable HTTP diagnostics without changing public APIs or protocol behavior.

Fixed

• Added missing Streamable HTTP access and JSON-RPC error diagnostics. Default
  records omit request paths, JSON-RPC request IDs, MCP session IDs, and remote
  network addresses; JSON-RPC error messages are escaped for single-record
  logging.
  Thanks to @venti1112
  (#350).
• Isolated application LogHandler failures from StreamableMcpServer
  diagnostics so those logs cannot change server behavior or protocol
  responses.
• Restored clean static analysis and formatting with Dart 3.13
  (#361).