fix: correct Gemini embedding model dimensions

- Fix gemini-embedding-001 dimension from 3072 to 768 in embeddingModels.ts
- Update documentation comment in gemini.ts to reflect correct dimension
- Update test expectations in service-factory.spec.ts

This fixes the vector dimension mismatch error when using Gemini text-embedding-004
with Qdrant, where vectors with incorrect dimensions (1024 or 3072) were being sent
to Qdrant which expects 768-dimensional vectors.

Fixes #7348

src/services/code-index/__tests__/service-factory.spec.ts

@@ -566,7 +566,7 @@ describe("CodeIndexServiceFactory", () => {
 				qdrantApiKey: "test-key",
 			}
 			mockConfigManager.getConfig.mockReturnValue(testConfig as any)
-			mockGetModelDimension.mockReturnValue(3072)
+			mockGetModelDimension.mockReturnValue(768)
 
 			// Act
 			factory.createVectorStore()
@@ -576,7 +576,7 @@ describe("CodeIndexServiceFactory", () => {
 			expect(MockedQdrantVectorStore).toHaveBeenCalledWith(
 				"/test/workspace",
 				"http://localhost:6333",
-				3072,
+				768,
 				"test-key",
 			)
 		})
@@ -590,7 +590,7 @@ describe("CodeIndexServiceFactory", () => {
 			}
 			mockConfigManager.getConfig.mockReturnValue(testConfig as any)
 			mockGetDefaultModelId.mockReturnValue("gemini-embedding-001")
-			mockGetModelDimension.mockReturnValue(3072)
+			mockGetModelDimension.mockReturnValue(768)
 
 			// Act
 			factory.createVectorStore()
@@ -601,7 +601,7 @@ describe("CodeIndexServiceFactory", () => {
 			expect(MockedQdrantVectorStore).toHaveBeenCalledWith(
 				"/test/workspace",
 				"http://localhost:6333",
-				3072,
+				768,
 				"test-key",
 			)
 		})

src/services/code-index/embedders/gemini.ts

@@ -11,7 +11,7 @@ import { TelemetryService } from "@roo-code/telemetry"
  *
  * Supported models:
  * - text-embedding-004 (dimension: 768)
- * - gemini-embedding-001 (dimension: 2048)
+ * - gemini-embedding-001 (dimension: 768)
  */
 export class GeminiEmbedder implements IEmbedder {
 	private readonly openAICompatibleEmbedder: OpenAICompatibleEmbedder

src/shared/embeddingModels.ts

@@ -48,7 +48,7 @@ export const EMBEDDING_MODEL_PROFILES: EmbeddingModelProfiles = {
 	},
 	gemini: {
 		"text-embedding-004": { dimension: 768 },
-		"gemini-embedding-001": { dimension: 3072, scoreThreshold: 0.4 },
+		"gemini-embedding-001": { dimension: 768, scoreThreshold: 0.4 },
 	},
 	mistral: {
 		"codestral-embed-2505": { dimension: 1536, scoreThreshold: 0.4 },