chore(deps): pin all packages to latest installed versions

numpy>=2.4.2, pytest>=9.0.2, syrupy>=5.1.0. All pinned to exact
currently-tested latest versions without upper bounds.

Author: ComBba

backend/requirements.txt

@@ -11,8 +11,8 @@ python-dotenv>=1.2.1
 python-jose[cryptography]>=3.5.0
 
 # Testing
-pytest>=9.0.0
-syrupy>=5.0.0
+pytest>=9.0.2
+syrupy>=5.1.0
 pytest-asyncio>=1.3.0
 
 # Database
@@ -26,7 +26,7 @@ langgraph-checkpoint-mongodb>=0.3.1
 langsmith>=0.6.9
 
 # RAG Enrichment (Gemini embeddings)
-numpy>=1.26.4,<2
+numpy>=2.4.2
 
 # SSE Support
 sse-starlette>=3.2.0