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/utils/time_estimator.py

@@ -0,0 +1,72 @@
+import time
+
+
+class TimeEstimator:
+
+    def __init__(self, total_iter: int, step_size: int, ema_alpha: float = 0.7):
+        self.avg_time_window = []  # window-based average
+        self.exp_avg_time = None  # exponential moving average
+        self.alpha = ema_alpha  # for exponential moving average
+
+        self.last_time = time.time()  # would not be accurate for the first iteration but well
+        self.total_iter = total_iter
+        self.step_size = step_size
+
+        self._buffering_exp = True
+
+    # call this at a fixed interval
+    # does not have to be every step
+    def update(self):
+        curr_time = time.time()
+        time_per_iter = curr_time - self.last_time
+        self.last_time = curr_time
+
+        self.avg_time_window.append(time_per_iter)
+
+        if self._buffering_exp:
+            if self.exp_avg_time is not None:
+                # discard the first iteration call to not pollute the ema
+                self._buffering_exp = False
+            self.exp_avg_time = time_per_iter
+        else:
+            self.exp_avg_time = self.alpha * self.exp_avg_time + (1 - self.alpha) * time_per_iter
+
+    def get_est_remaining(self, it: int):
+        if self.exp_avg_time is None:
+            return 0
+
+        remaining_iter = self.total_iter - it
+        return remaining_iter * self.exp_avg_time / self.step_size
+
+    def get_and_reset_avg_time(self):
+        avg = sum(self.avg_time_window) / len(self.avg_time_window) / self.step_size
+        self.avg_time_window = []
+        return avg
+
+
+class PartialTimeEstimator(TimeEstimator):
+    """
+    Used where the start_time and the end_time do not align
+    """
+
+    def update(self):
+        raise RuntimeError('Please use start() and end() for PartialTimeEstimator')
+
+    def start(self):
+        self.last_time = time.time()
+
+    def end(self):
+        assert self.last_time is not None, 'Please call start() before calling end()'
+        curr_time = time.time()
+        time_per_iter = curr_time - self.last_time
+        self.last_time = None
+
+        self.avg_time_window.append(time_per_iter)
+
+        if self._buffering_exp:
+            if self.exp_avg_time is not None:
+                # discard the first iteration call to not pollute the ema
+                self._buffering_exp = False
+            self.exp_avg_time = time_per_iter
+        else:
+            self.exp_avg_time = self.alpha * self.exp_avg_time + (1 - self.alpha) * time_per_iter