feat(api): use Tencent ASR flash with 16k_zh_large and dev transcript logs

Replace CreateRecTask polling with recording-file flash API, add TENCENT_APP_ID,
remove server-side pydub slicing, and log ASR recognition text at INFO in development.

Co-authored-by: Cursor <cursoragent@cursor.com>

api/tests/test_asr_transcript_logging.py

@@ -0,0 +1,58 @@
+"""ASR transcript logging helpers."""
+
+from app.core.agent_logging import asr_transcript_log_enabled, log_asr_transcript_result
+
+
+def test_asr_transcript_log_enabled_in_development(
+    monkeypatch,
+) -> None:
+    from app.core.config import settings
+
+    monkeypatch.setattr(settings, "app_environment", "development", raising=False)
+    monkeypatch.setattr(settings, "log_level", "INFO", raising=False)
+    assert asr_transcript_log_enabled() is True
+
+
+def test_asr_transcript_log_disabled_in_production_info(
+    monkeypatch,
+) -> None:
+    from app.core.config import settings
+
+    monkeypatch.setattr(settings, "app_environment", "production", raising=False)
+    monkeypatch.setattr(settings, "log_level", "INFO", raising=False)
+    assert asr_transcript_log_enabled() is False
+
+
+def test_log_asr_transcript_result_emits_info(
+    monkeypatch,
+    caplog,
+) -> None:
+    import logging
+
+    from app.core.config import settings
+
+    caplog.set_level(logging.INFO)
+    monkeypatch.setattr(settings, "app_environment", "development", raising=False)
+
+    class _Logger:
+        def info(self, msg, *args):
+            caplog.records.append(
+                logging.LogRecord(
+                    name="test",
+                    level=logging.INFO,
+                    pathname="",
+                    lineno=0,
+                    msg=msg.format(*args) if args else msg,
+                    args=(),
+                    exc_info=None,
+                )
+            )
+
+    log_asr_transcript_result(
+        _Logger(),
+        text="你好世界",
+        conversation_id="c1",
+        segment_index=0,
+    )
+    messages = [r.getMessage() for r in caplog.records]
+    assert any("ASR 识别结果" in m and "你好世界" in m for m in messages)