fix: Remove unreachable error pattern and superfluous type spec

- Remove unreachable {:error, _} pattern in result case statement
- Remove redundant iodata_to_charlist @SPEC (type inference sufficient)
- handle_response throws instead of returning errors

Author: GSMLG-BOT

lib/http.ex

@@ -426,10 +426,6 @@ defmodule HTTP do
                 %Response{status: status} ->
                   # Streaming response - we'll emit telemetry when streaming completes
                   HTTP.Telemetry.request_stop(status, request.url, 0, duration)
-
-                {:error, _} ->
-                  # Error will be handled in catch block
-                  :ok
               end
 
               result

lib/http/request.ex

@@ -147,7 +147,6 @@ defmodule HTTP.Request do
   # Efficiently converts iodata (nested list of binaries) to charlist
   # This is used for multipart form data to minimize intermediate copies
   # The iodata structure is flattened once instead of concatenating strings multiple times
-  @spec iodata_to_charlist(binary() | iodata()) :: charlist()
   defp iodata_to_charlist(iodata) do
     iodata
     |> IO.iodata_to_binary()