feat: add /api/v1/language endpoint for Go/Python runtime detection (#16952)

Both backends serve GET /api/v1/language. Frontend calls it once and
caches. By this way, front end can know the backend is go or python and
thus can determine which part of logic to load.

---------

Co-authored-by: Claude <noreply@anthropic.com>

web/src/services/knowledge-service.ts

@@ -19,6 +19,7 @@ const {
   documentThumbnails,
   documentIngest,
   listTagByKnowledgeIds,
+  listPipelines,
   setMeta,
   getMeta,
   getMetaKeys,
@@ -66,6 +67,10 @@ const methods = {
     url: retrievalTestShare,
     method: 'post',
   },
+  listPipelines: {
+    url: listPipelines,
+    method: 'get',
+  },
   pipelineRerun: {
     url: api.pipelineRerun,
     method: 'post',