[结束提示音]：完成对话结束音效提示，包含本地短音生成、恢复待机播放和配置测试

src/owner_voice_pet/tts.py

@@ -144,6 +144,36 @@ def _normalize_spoken_text(text: str) -> str:
     return clean.strip(" \t\r\n，,；;：:")
 
 
+def make_prompt_chime(
+    *,
+    frequency_hz: int = 880,
+    duration_ms: int = 140,
+    sample_rate: int = 16000,
+    channels: int = 1,
+) -> AudioSegment:
+    duration_ms = max(20, duration_ms)
+    sample_rate = max(8000, sample_rate)
+    channels = max(1, channels)
+    samples = int(sample_rate * duration_ms / 1000)
+    fade_samples = max(1, min(samples // 2, int(sample_rate * 0.015)))
+    pcm = bytearray()
+    for idx in range(samples):
+        fade_in = idx / fade_samples if idx < fade_samples else 1.0
+        fade_out = (samples - idx - 1) / fade_samples if idx >= samples - fade_samples else 1.0
+        envelope = max(0.0, min(1.0, fade_in, fade_out))
+        value = int(math.sin(2 * math.pi * frequency_hz * idx / sample_rate) * 9000 * envelope)
+        packed = struct.pack("<h", value)
+        pcm.extend(packed * channels)
+    return AudioSegment(
+        bytes(pcm),
+        sample_rate,
+        channels,
+        0,
+        duration_ms,
+        {"chime": "end", "text": "end_chime"},
+    )
+
+
 class SentenceBuffer:
     def __init__(self, max_chars: int = 80) -> None:
         self.max_chars = max_chars