feat: support interns2 preview time-series encoder

[CUHKSZzxy]

Summary

• Add InternS2 Preview encoder-only time-series support in a separated PyTorch/VL model path.
• Keep the InternS1-Pro time-series encoder rename and shared Whisper K-proj bias loader fix.
• Skip packaged time-series forecaster checkpoint tensors during loading without exposing forecast API/runtime paths.

Validation

• python -m py_compile on touched Python files
• pytest tests/test_lmdeploy/test_vl/test_preprocess_utils.py -q
• pre-commit hooks from git commit

Assistance

Assisted with Codex + GPT-5.6-Sol xHigh, reviewed manually