Add AI parsing capabilities for debt information and update database schema

- Implemented AI-powered parsing for debt emails using Google's Gemini model.
- Enhanced Postmark webhook to extract debt details including amount, vendor, description, due date, and legitimacy.
- Updated database schema to include new columns for AI-extracted data.
- Added environment variable requirements and updated package dependencies.
- Created migration script for new database columns and indexes.

.env.example

@@ -0,0 +1,10 @@
+# Environment variables for Inbox Negotiator
+
+# Supabase Configuration
+SUPABASE_URL=your_supabase_url_here
+SUPABASE_ANON_KEY=your_supabase_anon_key_here
+
+# Google Generative AI API Key for Gemini model
+GOOGLE_GENERATIVE_AI_API_KEY=your_google_api_key_here
+
+# Add these same variables to your actual .env file