Fix Mistral package version - use >=0.0.7 instead of >=1.0.0

The mistralai package doesn't have a 1.0.0 release yet. Using >=0.0.7 which is the stable version.

requirements.txt

@@ -1,6 +1,6 @@
 # Core Dependencies
 groq>=0.13.0  # Updated for httpx compatibility
-mistralai>=1.0.0  # Mistral AI - 1B tokens/month
+mistralai>=0.0.7  # Mistral AI - 1B tokens/month (corrected version)
 python-dotenv==1.0.0
 
 # Data Processing