[Feature][Quant] Reapply auto-detect quantization format and support remote model ID (#7111)

### What this PR does / why we need it?
Reapply the auto-detect quantization format feature (originally in
#6645, reverted in #6873) and extend it to support remote model
identifiers (e.g., `org/model-name`).

Changes:
- Reapply auto-detection of quantization method from model files
(`quant_model_description.json` for ModelSlim, `config.json` for
compressed-tensors)
- Add `get_model_file()` utility to handle file retrieval from both
local paths and remote repos (HuggingFace Hub / ModelScope)
- Update `detect_quantization_method()` to accept remote repo IDs with
optional `revision` parameter
- Update `maybe_update_config()` to work with remote model identifiers
- Add platform-level `auto_detect_quantization` support
- Add unit tests and e2e tests for both local and remote model ID
scenarios

Closes #6836

### Does this PR introduce _any_ user-facing change?

Yes. When `--quantization` is not explicitly specified, vllm-ascend will
now automatically detect the quantization format from the model files
for both local directories and remote model IDs.

- vLLM version: v0.16.0
- vLLM main:
4034c3d32e
---------
Signed-off-by: SlightwindSec <slightwindsec@gmail.com>

vllm_ascend/platform.py

@@ -178,6 +178,11 @@ class NPUPlatform(Platform):
 
     @classmethod
     def check_and_update_config(cls, vllm_config: VllmConfig) -> None:
+        from vllm_ascend.quantization.utils import maybe_auto_detect_quantization
+
+        if vllm_config.model_config is not None:
+            maybe_auto_detect_quantization(vllm_config)
+
         # initialize ascend config from vllm additional_config
         cls._fix_incompatible_config(vllm_config)
         ascend_config = init_ascend_config(vllm_config)