feat: Refactor data processing pipeline with AI cost tracking and enhanced session management

- Updated environment configuration to include Postgres database settings.
- Enhanced import processing to minimize field copying and rely on AI for analysis.
- Implemented detailed AI processing request tracking, including token usage and costs.
- Added new models for Question and SessionQuestion to manage user inquiries separately.
- Improved session processing scheduler with AI cost reporting functionality.
- Created a test script to validate the refactored pipeline and display processing statistics.
- Updated Prisma schema and migration files to reflect new database structure and relationships.

.gitignore

@@ -261,3 +261,6 @@ Thumbs.db
 /playwright-report/
 /blob-report/
 /playwright/.cache/
+
+# OpenAI API request samples
+sample-openai-request.json