Refa: improve image table context (#12244)

### What problem does this PR solve?

Improve image table context.

Current strategy in attach_media_context:

- Order by position when possible: if any chunk has page/position info,
sort by (page, top, left), otherwise keep original order.
- Apply only to media chunks: images use image_context_size, tables use
table_context_size.
- Primary matching: on the same page, choose a text chunk whose vertical
span overlaps the media, then pick the one with the closest vertical
midpoint.
- Fallback matching: if no overlap on that page, choose the nearest text
chunk on the same page (page-head uses the next text; page-tail uses the
previous text).
- Context extraction: inside the chosen text chunk, find a mid-sentence
boundary near the text midpoint, then take context_size tokens split
before/after (total budget).
- No multi-chunk stitching: context comes from a single text chunk to
avoid mixing unrelated segments.

### Type of change

- [x] Refactoring

---------

Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

web/src/components/chunk-method-dialog/index.tsx

@@ -220,15 +220,19 @@ export function ChunkMethodDialog({
 
   async function onSubmit(data: z.infer<typeof FormSchema>) {
     console.log('🚀 ~ onSubmit ~ data:', data);
+    const { image_table_context_window, ...parserConfig } = data.parser_config;
+    const imageTableContextWindow = Number(image_table_context_window || 0);
     const nextData = {
       ...data,
       parser_config: {
-        ...data.parser_config,
+        ...parserConfig,
+        image_context_size: imageTableContextWindow,
+        table_context_size: imageTableContextWindow,
         // Unset children delimiter if this option is not enabled
-        children_delimiter: data.parser_config.enable_children
-          ? data.parser_config.children_delimiter
+        children_delimiter: parserConfig.enable_children
+          ? parserConfig.children_delimiter
           : '',
-        pages: data.parser_config?.pages?.map((x: any) => [x.from, x.to]) ?? [],
+        pages: parserConfig?.pages?.map((x: any) => [x.from, x.to]) ?? [],
       },
     };
     console.log('🚀 ~ onSubmit ~ nextData:', nextData);
@@ -249,6 +253,10 @@ export function ChunkMethodDialog({
         parser_config: fillDefaultParserValue({
           pages: pages.length > 0 ? pages : [{ from: 1, to: 1024 }],
           ...omit(parserConfig, 'pages'),
+          image_table_context_window:
+            parserConfig?.image_table_context_window ??
+            parserConfig?.image_context_size ??
+            parserConfig?.table_context_size,
           // graphrag: {
           //   use_graphrag: get(
           //     parserConfig,

web/src/interfaces/database/document.ts

@@ -44,6 +44,9 @@ export interface IParserConfig {
   raptor?: Raptor;
   graphrag?: GraphRag;
   image_context_window?: number;
+  image_table_context_window?: number;
+  image_context_size?: number;
+  table_context_size?: number;
   mineru_parse_method?: 'auto' | 'txt' | 'ocr';
   mineru_formula_enable?: boolean;
   mineru_table_enable?: boolean;

web/src/interfaces/request/document.ts

@@ -8,6 +8,9 @@ export interface IChangeParserConfigRequestBody {
   auto_questions?: number;
   html4excel?: boolean;
   toc_extraction?: boolean;
+  image_table_context_window?: number;
+  image_context_size?: number;
+  table_context_size?: number;
 }
 
 export interface IChangeParserRequestBody {