Fix ParseError Access behavior error in packet batch insert

Fixed "ParseError does not implement the Access behaviour" error that
occurred during packet batch insert when packets contained ParseError
structs in their data_extended field.

Added special handling for Aprs.Types.ParseError structs in the
struct_to_map function to convert them to simple maps with their
error_code and message fields, preventing the Access behavior error
when the struct is accessed during processing.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

lib/aprsme/packet_consumer.ex

@@ -5,6 +5,7 @@ defmodule Aprsme.PacketConsumer do
   """
   use GenStage
 
+  alias Aprs.Types.ParseError
   alias Aprsme.LogSanitizer
   alias Aprsme.Repo
 
@@ -476,6 +477,15 @@ defmodule Aprsme.PacketConsumer do
 
   defp normalize_data_type(attrs), do: Aprsme.EncodingUtils.normalize_data_type(attrs)
 
+  defp struct_to_map(%{__struct__: ParseError} = error) do
+    # Handle ParseError specially to avoid Access behavior issues
+    %{
+      error_code: error.error_code,
+      message: error.message,
+      __original_struct__: ParseError
+    }
+  end
+
   defp struct_to_map(%{__struct__: struct_type} = struct) do
     converted_map =
       struct