chore: vendor selva_core from jnwnlee/selva@d7d40a9

Pure PyTorch SelVA source for SelvaModelLoader/FeatureExtractor/Sampler nodes.
Imports rewritten from selva.* to selva_core.*. mel_converter.py: replaced
librosa.filters.mel with pure-numpy implementation to avoid librosa→numba→NumPy
version incompatibility in some ComfyUI environments.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

selva_core/model/utils/parameter_groups.py

@@ -0,0 +1,39 @@
+import logging
+
+log = logging.getLogger()
+
+
+def get_parameter_groups(model, cfg, print_log=False):
+    """
+    Assign different weight decays and learning rates to different parameters.
+    Returns a parameter group which can be passed to the optimizer.
+    """
+    weight_decay = cfg.weight_decay
+    base_lr = cfg.learning_rate
+
+    params = []
+
+    # inspired by detectron2
+    memo = set()
+    for name, param in model.named_parameters():
+        if not param.requires_grad:
+            continue
+        # Avoid duplicating parameters
+        if param in memo:
+            continue
+        memo.add(param)
+
+        if name.startswith('module'):
+            name = name[7:]
+
+        params.append(param)
+
+    parameter_groups = [
+        {
+            'params': params,
+            'lr': base_lr,
+            'weight_decay': weight_decay
+        },
+    ]
+
+    return parameter_groups