Enhance table title handling and improve heading detection logic

- Added logic to set `table_title` from `caption` if it is under 160 characters and not already set.
- Updated `_blocks_from_content_list` to assign `table_title` based on `caption` length.
- Introduced new regex patterns for better detection of TOC entries and noise.
- Enhanced heading detection to differentiate between numbered instructions and actual headings.
- Added tests to verify that table captions are correctly assigned as titles and that numbered instructions are treated as body text.

backend/tests/test_mineru_adapter.py

@@ -134,6 +134,21 @@ class MineruAdapterMappingTest(unittest.TestCase):
         self.assertEqual(blocks[0].type, BlockType.PARAGRAPH)
         self.assertTrue(blocks[0].meta.get("is_footnote"))
 
+    def test_table_caption_becomes_table_title(self) -> None:
+        items = [
+            {
+                "type": "table",
+                "table_body": "| Field | Description |\n| --- | --- |\n| id | Identifier |",
+                "table_caption": ["第一节 综合资讯栏"],
+                "page_idx": 7,
+            }
+        ]
+
+        blocks = _blocks_from_content_list(items, Path("content_list.json"), Path("assets"))
+
+        self.assertEqual(len(blocks), 1)
+        self.assertEqual(blocks[0].meta.get("table_title"), "第一节 综合资讯栏")
+
     def test_list_items_become_paragraph(self) -> None:
         items = [
             {