feat: add image context window in dataset config (#12094)

### What problem does this PR solve?

Add image context window configuration in **Dataset** >
**Configduration** and **Dataset** > **Files** > **Parse** > **Ingestion
Pipeline** (**Chunk Method** modal)

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

web/src/pages/dataset/dataset-setting/form-schema.ts

@@ -32,6 +32,7 @@ export const formSchema = z
         tag_kb_ids: z.array(z.string()).nullish(),
         topn_tags: z.number().optional(),
         toc_extraction: z.boolean().optional(),
+        image_context_window: z.number().optional(),
         overlapped_percent: z.number().optional(),
         // MinerU-specific options
         mineru_parse_method: z.enum(['auto', 'txt', 'ocr']).optional(),