FEATURE: Move the default embeddings model to bge-large-en (#417)

config/settings.yml

@@ -231,7 +231,7 @@ discourse_ai:
   ai_embeddings_model:
     type: enum
     list_type: compact
-    default: "all-mpnet-base-v2"
+    default: "bge-large-en"
     allow_any: false
     choices:
       - all-mpnet-base-v2

spec/lib/modules/ai_bot/tools/search_spec.rb

@@ -80,7 +80,7 @@ RSpec.describe DiscourseAi::AiBot::Tools::Search do
         post1 = Fabricate(:post, topic: topic_with_tags)
         search = described_class.new({ search_query: "hello world, sam", status: "public" })
 
-        DiscourseAi::Embeddings::VectorRepresentations::AllMpnetBaseV2
+        DiscourseAi::Embeddings::VectorRepresentations::BgeLargeEn
           .any_instance
           .expects(:asymmetric_topics_similarity_search)
           .returns([post1.topic_id])

spec/lib/modules/embeddings/jobs/generate_embeddings_spec.rb

@@ -7,7 +7,7 @@ RSpec.describe Jobs::GenerateEmbeddings do
     before do
       SiteSetting.ai_embeddings_discourse_service_api_endpoint = "http://test.com"
       SiteSetting.ai_embeddings_enabled = true
-      SiteSetting.ai_embeddings_model = "all-mpnet-base-v2"
+      SiteSetting.ai_embeddings_model = "bge-large-en"
     end
 
     fab!(:topic) { Fabricate(:topic) }

spec/lib/modules/embeddings/semantic_search_spec.rb

@@ -24,7 +24,7 @@ RSpec.describe DiscourseAi::Embeddings::SemanticSearch do
     after { described_class.clear_cache_for(query) }
 
     def stub_candidate_ids(candidate_ids)
-      DiscourseAi::Embeddings::VectorRepresentations::AllMpnetBaseV2
+      DiscourseAi::Embeddings::VectorRepresentations::BgeLargeEn
         .any_instance
         .expects(:asymmetric_topics_similarity_search)
         .returns(candidate_ids)

spec/lib/modules/embeddings/semantic_topic_query_spec.rb

@@ -12,7 +12,7 @@ describe DiscourseAi::Embeddings::EntryPoint do
       fab!(:target) { Fabricate(:topic) }
 
       def stub_semantic_search_with(results)
-        DiscourseAi::Embeddings::VectorRepresentations::AllMpnetBaseV2
+        DiscourseAi::Embeddings::VectorRepresentations::BgeLargeEn
           .any_instance
           .expects(:symmetric_topics_similarity_search)
           .returns(results.concat([target.id]))

spec/support/embeddings_generation_stubs.rb

@@ -3,6 +3,7 @@
 class EmbeddingsGenerationStubs
   class << self
     def discourse_service(model, string, embedding)
+      model = "bge-large-en-v1.5" if model == "bge-large-en"
       WebMock
         .stub_request(
           :post,