[1/N][refactor] torchair deepseek modeling refactor (#2384)

### What this PR does / why we need it?

Move torchair related model arch into torchair moduel to make the code
clear. Next step we'll remove all torchair related code outside of
torchair moduel.

### Does this PR introduce _any_ user-facing change?
No.

- vLLM version: v0.10.0
- vLLM main:
08d5f7113a

Signed-off-by: linfeng-yuan <1102311262@qq.com>

tests/ut/torchair/test_utils.py

@@ -1,4 +1,6 @@
 import os
+from concurrent.futures import ThreadPoolExecutor
+from unittest.mock import MagicMock, patch
 
 from tests.ut.base import TestBase
 from vllm_ascend.torchair import utils
@@ -26,3 +28,46 @@ class TestTorchairUtils(TestBase):
                          "Delete torchair cache dir failed")
         self.assertFalse(utils.check_kv_cache_bytes_cache_exist(),
                          "Delete kv cache bytes cache dir failed")
+
+    def test_torchair_cache_dir_multiple_ranks(self):
+        ranks = [0, 1, 2, 3]
+        values = [100, 200, 300, 400]
+
+        with ThreadPoolExecutor() as executor:
+            executor.map(utils.write_kv_cache_bytes_to_file, ranks, values)
+        for rank, expected in zip(ranks, values):
+            self.assertEqual(expected,
+                             utils.read_kv_cache_bytes_from_file(rank))
+        utils.delete_torchair_cache_file()
+
+        self.assertFalse(utils.check_torchair_cache_exist(),
+                         "Delete torchair cache dir failed")
+        self.assertFalse(utils.check_kv_cache_bytes_cache_exist(),
+                         "Delete kv cache bytes cache dir failed")
+
+    @patch('vllm.ModelRegistry')
+    def test_register_torchair_model(self, mock_model_registry):
+        mock_registry = MagicMock()
+        mock_model_registry.return_value = mock_registry
+        utils.register_torchair_model()
+
+        self.assertEqual(mock_model_registry.register_model.call_count, 3)
+        call_args_list = mock_model_registry.register_model.call_args_list
+
+        expected_registrations = [
+            ("DeepSeekMTPModel",
+             "vllm_ascend.torchair.models.torchair_deepseek_mtp:TorchairDeepSeekMTP"
+             ),
+            ("DeepseekV2ForCausalLM",
+             "vllm_ascend.torchair.models.torchair_deepseek_v2:TorchairDeepseekV2ForCausalLM"
+             ),
+            ("DeepseekV3ForCausalLM",
+             "vllm_ascend.torchair.models.torchair_deepseek_v3:TorchairDeepseekV3ForCausalLM"
+             )
+        ]
+
+        for i, (expected_name,
+                expected_path) in enumerate(expected_registrations):
+            args, kwargs = call_args_list[i]
+            self.assertEqual(args[0], expected_name)
+            self.assertEqual(args[1], expected_path)