Please address the comments from this code review:

## Overall Comments
- In `normalize_openai_compatible_embedding_api_base`, a host without scheme (e.g. `api.openai.com`) is treated as a path and returned unchanged, which produces an invalid base URL; consider either auto-prefixing `https://` or explicitly validating and rejecting scheme-less values to avoid confusing runtime failures.
- The new `send_dimensions_param` flag is parsed quite liberally via `should_send_dimensions_param` (accepting various stringy truthy values); if config is only ever stored as a native boolean, you could simplify this to a direct bool read and avoid surprising behavior when unconventional strings are passed in.

## Individual Comments

### Comment 1
<location path="tests/test_openai_compatible_embedding_source.py" line_range="72-81" />
<code_context>
     assert data["status"] == "ok" and "platform" in data["data"]


+@pytest.mark.asyncio
+async def test_provider_template_exposes_openai_compatible_embedding_presets(
+    app: Quart,
</code_context>
<issue_to_address>
**suggestion (testing):** Add assertions that `terminate()` properly closes the underlying AsyncOpenAI client

Current tests call `terminate()` in `finally` blocks but never verify that the underlying client is closed. Since `_FakeAsyncOpenAI` tracks `closed`, please add assertions (e.g., `assert provider_without_dimensions.client.closed is True` or via `instances`) after `terminate()` to validate resource cleanup and catch regressions in connection handling.
</issue_to_address>

### Comment 2
<location path="docs/en/use/knowledge-base.md" line_range="25" />
<code_context>
+> `OpenAI Compatible Embedding` includes a `send_dimensions_param` switch. When enabled, AstrBot sends `embedding_dimensions` to the upstream embedding API as the `dimensions` parameter. Disable it for OpenAI-compatible services that only need the local vector size and do not support `dimensions`.
+
+> [!NOTE]
+> The Volcengine preset defaults to `doubao-embedding-vision`. AstrBot's knowledge-base pipeline is still text chunking plus text embedding only, so this integration uses the model with text input only and does not add multimodal knowledge-base support yet,although it is a multimodal embedding model.
+
+> [!NOTE]
</code_context>
<issue_to_address>
**issue (typo):** Add a space after the comma in "yet,although" to fix the typo.

Please insert a space after the comma so it reads "yet, although it is a multimodal embedding model."

```suggestion
> The Volcengine preset defaults to `doubao-embedding-vision`. AstrBot's knowledge-base pipeline is still text chunking plus text embedding only, so this integration uses the model with text input only and does not add multimodal knowledge-base support yet, although it is a multimodal embedding model.
```
</issue_to_address>