Fix vLLM vector embeddings URL construction to preserve custom API path prefixes (#5350)

* Initial plan

* fix: use trimV1 and url-join for vLLM vector embeddings URL construction

Fixes URL path construction in vllm-vectors.js to preserve custom API
path prefixes (e.g. /compatible-mode/v1). Previously url.pathname
assignment would overwrite the entire path, stripping any prefix.

Now uses the same trimV1 + urlJoin pattern as llamacpp-vectors.js.

Co-authored-by: Cohee1207 <18619528+Cohee1207@users.noreply.github.com>
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* Revert package-lock

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Cohee1207 <18619528+Cohee1207@users.noreply.github.com>

src/vectors/vllm-vectors.js

@@ -1,6 +1,8 @@
 import fetch from 'node-fetch';
+import urlJoin from 'url-join';
 import { setAdditionalHeadersByType } from '../additional-headers.js';
 import { TEXTGEN_TYPES } from '../constants.js';
+import { trimV1 } from '../util.js';
 
 /**
  * Gets the vector for the given text from VLLM
@@ -11,8 +13,7 @@ import { TEXTGEN_TYPES } from '../constants.js';
  * @returns {Promise<number[][]>} - The array of vectors for the texts
  */
 export async function getVllmBatchVector(texts, apiUrl, model, directories) {
-    const url = new URL(apiUrl);
-    url.pathname = '/v1/embeddings';
+    const url = new URL(urlJoin(trimV1(apiUrl), '/v1/embeddings'));
 
     const headers = {};
     setAdditionalHeadersByType(headers, TEXTGEN_TYPES.VLLM, apiUrl, directories);