Refactor document handling and update Milvus collection settings

- Removed multiple failed document entries from `documents.json`.
- Added a new document entry with updated metadata and changed the index name to `regulations_dense_1024_v2`.
- Updated architecture documentation to reflect changes in the Milvus collection name.
- Adjusted requirements by removing the sqlalchemy dependency.
- Modified test cases to align with new document structure and naming conventions.
- Introduced a new test file for Milvus vector index runtime recovery and error handling.
- Updated assertions in various test files to ensure compatibility with the new schema.

backend/app/infrastructure/parser/local_chunk_builder.py

@@ -10,6 +10,7 @@ class LocalRegulationChunkBuilder(ChunkBuilder):
     """Adapt the existing markdown chunker to the new chunk builder port."""
 
     def __init__(self, *, chunk_size: int = 512, chunk_overlap: int = 50) -> None:
+        """Initialize the local markdown chunk builder."""
         self.chunker = RegulationChunker(
             chunk_size=chunk_size,
             chunk_overlap=chunk_overlap,
@@ -22,6 +23,7 @@ class LocalRegulationChunkBuilder(ChunkBuilder):
         regulation_type: str,
         version: str,
     ) -> list[Chunk]:
+        """Build migrated chunk objects from the legacy markdown chunker output."""
         markdown_text = parsed_document.raw_text.strip()
         if not markdown_text:
             return []
@@ -50,16 +52,18 @@ class LocalRegulationChunkBuilder(ChunkBuilder):
                 Chunk(
                     chunk_id=item.metadata.chunk_id,
                     doc_id=parsed_document.doc_id,
-                    doc_name=parsed_document.doc_name,
-                    content=item.content,
+                    doc_title=parsed_document.doc_name,
+                    text=item.content,
                     embedding_text=item.content,
+                    chunk_type="local_markdown_chunk",
                     section_title=item.metadata.section_title or item.metadata.section_number,
                     section_path=section_path,
-                    page_number=item.metadata.page_number,
+                    page_start=item.metadata.page_number,
+                    page_end=item.metadata.page_number,
+                    section_level=len(section_path),
                     regulation_type=regulation_type,
                     version=version,
                     semantic_id=item.metadata.clause_number,
-                    block_type="local_markdown_chunk",
                     metadata=metadata,
                 )
             )