fix: remove hardcoded dimension fallback to respect UI settings

- Removed hardcoded fallback value (1536) from codebaseIndexEmbedderModelDimension in ClineProvider.ts
- This allows the proper dimension resolution hierarchy to work:
  1. User-configured dimension from UI settings
  2. Model-specific defaults from embedding model profiles
  3. System defaults handled by service factory
- Fixes issue where UI-configured dimensions were being ignored

Fixes #5754

Author: roomote

src/core/webview/ClineProvider.ts

@@ -1867,7 +1867,7 @@ export class ClineProvider
 				codebaseIndexEmbedderProvider: codebaseIndexConfig?.codebaseIndexEmbedderProvider ?? "openai",
 				codebaseIndexEmbedderBaseUrl: codebaseIndexConfig?.codebaseIndexEmbedderBaseUrl ?? "",
 				codebaseIndexEmbedderModelId: codebaseIndexConfig?.codebaseIndexEmbedderModelId ?? "",
-				codebaseIndexEmbedderModelDimension: codebaseIndexConfig?.codebaseIndexEmbedderModelDimension ?? 1536,
+				codebaseIndexEmbedderModelDimension: codebaseIndexConfig?.codebaseIndexEmbedderModelDimension,
 				codebaseIndexOpenAiCompatibleBaseUrl: codebaseIndexConfig?.codebaseIndexOpenAiCompatibleBaseUrl,
 				codebaseIndexSearchMaxResults: codebaseIndexConfig?.codebaseIndexSearchMaxResults,
 				codebaseIndexSearchMinScore: codebaseIndexConfig?.codebaseIndexSearchMinScore,