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/vectorstore/cross_encoder_reranker.py

@@ -31,7 +31,7 @@ class OpenAICompatibleReranker(Reranker):
         if not chunks:
             return []
 
-        texts = [chunk.content for chunk in chunks]
+        texts = [chunk.text for chunk in chunks]
         start = time.time()
         try:
             scores = self._call_reranker(query, texts)