Please address the comments from this code review:

## Overall Comments
- The `timeout` value from the provider config is stored but never used when calling `MultiModalConversation.call`; consider passing it through (if supported) or removing the setting to avoid confusion.
- In `_prepare_audio`, temporary files created when downloading from a URL (the initial `path` before any conversion) are never cleaned up, which can leak files in the temp directory; consider tracking and removing the downloaded temp file in `finally`.
- `_get_audio_format` is defined as `async` but only performs synchronous file I/O and is awaited in one place; consider making it a regular synchronous method to simplify usage and avoid unnecessary `await`.

## Individual Comments

### Comment 1
<location path="astrbot/core/provider/sources/qwen_asr_flash_source.py" line_range="59-68" />
<code_context>
+        self.timeout = provider_config.get("timeout", 30)
</code_context>
<issue_to_address>
**issue (bug_risk):** The configured timeout value is stored but not applied to the DashScope API call.

`timeout` is read from `provider_config`, but `MultiModalConversation.call` is not given any timeout-related argument, so this value is never used. If the DashScope client exposes a timeout option (e.g., `request_timeout`), pass `self.timeout` through so the config actually controls request duration and avoids indefinitely hanging calls.
</issue_to_address>

### Comment 2
<location path="astrbot/core/provider/sources/qwen_asr_flash_source.py" line_range="110-119" />
<code_context>
+        output_path = None
+
+        # Download from URL if needed
+        if audio_url.startswith("http"):
+            if "multimedia.nt.qq.com.cn" in audio_url:
+                is_tencent = True
+
+            temp_dir = get_astrbot_temp_path()
+            path = os.path.join(
+                temp_dir,
+                f"qwen_asr_{os.urandom(4).hex()}.input",
+            )
+            await download_file(audio_url, path)
+            audio_url = path
+
</code_context>
<issue_to_address>
**suggestion:** Preserving the original file extension when downloading could improve MIME detection for base64 encoding.

Because downloaded files are saved with a `.input` suffix, `_get_mime_type` always falls back to the default `audio/mpeg` for these URLs. If you derive and reuse the original extension from the remote URL (e.g., `.wav`, `.mp3`, `.ogg`) in the temp filename, `_get_mime_type` can infer a more accurate MIME type and better match what the API expects.

Suggested implementation:

```python
import base64
import os
import pathlib
from urllib.parse import urlparse

import dashscope
from dashscope import MultiModalConversation

```

```python
        is_tencent = False
        output_path = None

        # Download from URL if needed
        if audio_url.startswith("http"):
            if "multimedia.nt.qq.com.cn" in audio_url:
                is_tencent = True

            temp_dir = get_astrbot_temp_path()

            # Preserve original file extension (if present) to improve MIME detection
            parsed_url = urlparse(audio_url)
            _, ext = os.path.splitext(parsed_url.path)
            if not ext:
                ext = ".input"

            path = os.path.join(
                temp_dir,
                f"qwen_asr_{os.urandom(4).hex()}{ext}",
            )
            await download_file(audio_url, path)
            audio_url = path

```
</issue_to_address>

### Comment 3
<location path="astrbot/core/provider/sources/qwen_asr_flash_source.py" line_range="166" />
<code_context>
+        base64_str = base64.b64encode(file_path_obj.read_bytes()).decode()
+        return f"data:{mime_type};base64,{base64_str}"
+
+    async def get_text(self, audio_url: str) -> str:
+        """Transcribe audio file to text using Qwen3-ASR-Flash API.
+
</code_context>
<issue_to_address>
**issue (complexity):** Consider extracting response parsing into a helper, simplifying audio format detection, and optionally splitting out URL downloading to make `get_text` and `_prepare_audio` easier to follow without changing behaviour.

You can reduce complexity in a few focused spots without changing behaviour.

### 1. Flatten response parsing in `get_text`

The current parsing is quite nested and defensive. You can make it easier to follow by:

- Using `getattr(...)` with sane defaults.
- Normalising `content` into a list.
- Using a single dict branch and `.get()` calls.

Example:

```python
def _extract_text_from_response(self, response) -> str:
    if response.status_code != 200:
        error_msg = getattr(response, "message", None) or f"API error: {response.status_code}"
        logger.error(f"Qwen3-ASR-Flash API error: {error_msg}")
        raise Exception(f"Qwen3-ASR-Flash API error: {error_msg}")

    output = getattr(response, "output", None)
    choices = getattr(output, "choices", []) or []
    if not choices:
        return ""

    message = getattr(choices[0], "message", None)
    content = getattr(message, "content", "")

    # normalise to list
    if isinstance(content, str):
        return content.strip()
    if not isinstance(content, list):
        return ""

    parts: list[str] = []
    for item in content:
        if isinstance(item, dict):
            if "text" in item:
                parts.append(item.get("text", ""))
            elif "audio" in item:
                parts.append(item.get("audio", ""))
    return "".join(parts).strip()
```

Then `get_text` becomes:

```python
async def get_text(self, audio_url: str) -> str:
    output_path = None
    try:
        audio_path, output_path = await self._prepare_audio(audio_url)
        data_uri = self._encode_audio_base64(audio_path)

        messages = [{"role": "user", "content": [{"audio": data_uri}]}]
        asr_options = {"enable_itn": self.enable_itn}
        if self.language != "auto":
            asr_options["language"] = self.language

        response = MultiModalConversation.call(
            api_key=self.api_key,
            model=self.model,
            messages=messages,
            result_format="message",
            asr_options=asr_options,
        )

        text = self._extract_text_from_response(response)
        logger.debug(f"Qwen3-ASR-Flash transcription: {text}")
        return text

    except Exception as e:
        logger.error(f"Qwen3-ASR-Flash transcription error: {e}")
        raise
    finally:
        if output_path and os.path.exists(output_path):
            try:
                os.remove(output_path)
            except Exception as e:
                logger.error(f"Failed to remove temp file {output_path}: {e}")
```

This keeps all behaviour but separates orchestration from parsing and removes nested `hasattr` checks.

### 2. Make `_get_audio_format` synchronous

The method does only synchronous file I/O and header checks; making it async forces callers to `await` with no real benefit.

```python
def _get_audio_format(self, file_path: str) -> str | None:
    silk_header = b"SILK"
    amr_header = b"#!AMR"

    try:
        with open(file_path, "rb") as f:
            file_header = f.read(8)
    except FileNotFoundError:
        return None

    if silk_header in file_header:
        return "silk"
    if amr_header in file_header:
        return "amr"
    return None
```

And update `_prepare_audio` accordingly:

```python
elif (
    lower_audio_url.endswith(".amr")
    or lower_audio_url.endswith(".silk")
    or is_tencent
):
    file_format = self._get_audio_format(audio_url)

    if file_format in ["silk", "amr"]:
        temp_dir = get_astrbot_temp_path()
        output_path = os.path.join(temp_dir, f"qwen_asr_{os.urandom(4).hex()}.wav")

        if file_format == "silk":
            logger.info("Converting silk file to wav...")
            await tencent_silk_to_wav(audio_url, output_path)
        elif file_format == "amr":
            logger.info("Converting amr file to wav...")
            await convert_to_pcm_wav(audio_url, output_path)

        audio_url = output_path
```

This removes unnecessary async surface area while preserving functionality.

### 3. Optional: small helpers to clarify `_prepare_audio`

Without changing the logic, you can pull out URL handling to reduce branching inside `_prepare_audio`:

```python
async def _download_if_url(self, audio_url: str) -> tuple[str, bool]:
    if not audio_url.startswith("http"):
        return audio_url, False

    is_tencent = "multimedia.nt.qq.com.cn" in audio_url
    temp_dir = get_astrbot_temp_path()
    path = os.path.join(temp_dir, f"qwen_asr_{os.urandom(4).hex()}.input")
    await download_file(audio_url, path)
    return path, is_tencent
```

Then in `_prepare_audio`:

```python
async def _prepare_audio(self, audio_url: str) -> tuple[str, str | None]:
    audio_url, is_tencent = await self._download_if_url(audio_url)
    output_path = None

    if not os.path.exists(audio_url):
        raise FileNotFoundError(f"File not found: {audio_url}")

    lower_audio_url = audio_url.lower()

    if lower_audio_url.endswith(".opus"):
        ...
    elif lower_audio_url.endswith((".amr", ".silk")) or is_tencent:
        ...
    return audio_url, output_path
```

This keeps behaviour intact but makes the flow (download → conversion decisions) easier to follow.
</issue_to_address>