Add Devstral 2 (Ministral3) model support

Add Ministral3ForCausalLM architecture mapping and ministral3 tokenizer type
for Mistral AI's Devstral 2 models (Devstral-Small-2-24B, Devstral-2-123B).

These models use the same Mistral3 architecture, so they reuse the existing
Bumblebee.Text.Mistral3 implementation.

Author: dai-yamashita

lib/bumblebee.ex

@@ -174,6 +174,7 @@ defmodule Bumblebee do
     "Mistral3ForCausalLM" => {Bumblebee.Text.Mistral3, :for_causal_language_modeling},
     "Mistral3ForSequenceClassification" =>
       {Bumblebee.Text.Mistral3, :for_sequence_classification},
+    "Ministral3ForCausalLM" => {Bumblebee.Text.Mistral3, :for_causal_language_modeling},
     "Mistral3ForConditionalGeneration" =>
       {Bumblebee.Multimodal.Mistral3, :for_conditional_generation},
     "PhiModel" => {Bumblebee.Text.Phi, :base},
@@ -263,6 +264,7 @@ defmodule Bumblebee do
     "llama" => :llama,
     "mistral" => :llama,
     "mistral3" => :llama,
+    "ministral3" => :llama,
     "mbart" => :mbart,
     "phi" => :code_gen,
     "phi3" => :llama,