fix(deps): correct numpy and pytest version constraints

numpy>=1.26.4,<2: Python 3.12 requires numpy 1.26+, cap at <2 to avoid
ABI breakage. pytest>=9.0.0 with syrupy>=5.0.0: syrupy 5.x supports
pytest 9, removing the previous version conflict.

Author: ComBba

backend/requirements.txt

@@ -11,7 +11,8 @@ python-dotenv>=1.2.1
 python-jose[cryptography]>=3.5.0
 
 # Testing
-pytest>=8.0.0
+pytest>=9.0.0
+syrupy>=5.0.0
 pytest-asyncio>=1.3.0
 
 # Database
@@ -25,7 +26,7 @@ langgraph-checkpoint-mongodb>=0.3.1
 langsmith>=0.6.9
 
 # RAG Enrichment (Gemini embeddings)
-numpy>=1.24.0
+numpy>=1.26.4,<2
 
 # SSE Support
 sse-starlette>=3.2.0