Restore centroid demo artifacts

Restore small checkpoint centroid demo artifacts and document centroid-only demo usage. No training data, optimizer state, scheduler state, logs, generated samples, or local configs are added.

README.md

@@ -85,6 +85,33 @@ to synthesize. Reference clips should be at least 3 seconds. The
 speaker-reference-audio-only mode uses the raw reference-audio token path and
 does not require a reference transcript.
 
+## Centroid Demo
+
+This repository keeps two small centroid demo artifacts under `checkpoints/` so
+users can test the `centroid-only` path without building a centroid table first:
+
+- `checkpoints/hung_yi_lee_speaker_centroids.pt`
+- `checkpoints/speaker_centroids.pt`
+
+These files are demo speaker-conditioning artifacts only. They are not training
+data, optimizer state, scheduler state, logs, generated samples, or a complete
+speaker registry.
+
+```python
+import torch
+
+table = torch.load("checkpoints/speaker_centroids.pt", map_location="cpu")
+speaker_ids = table["speaker_ids"]
+centroids = table["centroids"]
+
+audio = model.generate(
+    target_text="這是 centroid-only 的測試。",
+    speaker_centroid=centroids[0],
+    cfg_value=2.0,
+    inference_timesteps=10,
+)
+```
+
 ## Long Text
 
 For long-form synthesis, split text into sentence-sized chunks and concatenate
@@ -127,4 +154,5 @@ Long-form diagnostics on the selected checkpoint:
 - `audiovae.pth`: AudioVAE weights.
 - `config.json`: BlueMagpie architecture/runtime config.
 - `tokenizer.json`, `tokenizer_config.json`: tokenizer files.
+- `checkpoints/*speaker_centroids.pt`: small centroid demo artifacts.
 - `USAGE.md`: expanded usage guide.

USAGE.md

@@ -55,6 +55,20 @@ wav = model.generate(
 
 ```
 
+Centroid demo:
+
+```python
+import torch
+
+table = torch.load(f"{model_dir}/checkpoints/speaker_centroids.pt", map_location="cpu")
+wav = model.generate(
+    target_text="這是 centroid demo 的測試。",
+    speaker_centroid=table["centroids"][0],
+    cfg_value=2.0,
+    inference_timesteps=10,
+)
+```
+
 Streaming:
 
 ```python