Features:
- Categories CSV import (API + frontend with drag & drop)
- Transactions CSV import with custom format (API + frontend)
- Smart account/institution creation during transaction import
- Auto-creation of category types and groups during category import
- Duplicate detection for both imports
- Rich description building from multiple CSV fields

Test Improvements:
- Created comprehensive test suite (142 tests total)
- 121/142 tests passing (85% pass rate, up from 62%)
- 100% of model tests passing (63/63)
- 96% of API tests passing (54/56)
- Added input validation to 5 API controllers

Documentation:
- Organized all documentation into /docs directory
- Created comprehensive INDEX.md for navigation
- New root README.md with project overview
- CATEGORIES_IMPORT_FEATURE.md - Complete feature documentation
- TRANSACTIONS_IMPORT_FEATURE.md - Complete feature documentation
- DOCUMENTATION_ORGANIZATION.md - Documentation structure guide

Bug Fixes:
- Fixed account creation 400 error on frontend
- Fixed validation to allow optional fields (None values)
- Added missing default fields to account creation form

Files Modified:
- api/account/controllers.py - Added validation
- api/categories/controllers.py - Added CSV import endpoint and validation
- api/institution/controllers.py - Added validation
- api/institution_account/controllers.py - Fixed validation logic
- api/transaction/controllers.py - Rewrote CSV import with new format
- app/categories/controllers.py - Added import route
- app/static/js/institution_account/institution_account.js - Added default fields
- app/templates/categories/index.html - Added import button
- app/templates/transactions/import.html - New drag & drop interface
- app/templates/transactions/index.html - Updated import button

Files Created:
- app/static/js/categories/import.js - Categories upload handler
- app/static/js/transactions/import.js - Transactions upload handler
- app/templates/categories/import.html - Categories import UI
- tests/ - Complete test suite (142 tests)
- docs/ - All documentation moved here
- .coveragerc - Coverage configuration
- pytest.ini - Pytest configuration