…ies, and transactions

Features:
- Edit functionality with pre-populated forms for all entities
- Delete functionality with confirmation dialogs
- Referential integrity checks to prevent orphaned records
- Edit modals with dropdowns for related data (institutions, categories, accounts)
- Real-time form population via API GET endpoints

API Endpoints Added:
- GET /api/institution/<id> - Get single institution
- PUT /api/institution/<id> - Update institution
- DELETE /api/institution/<id> - Delete institution with account check
- GET /api/institution/account/<id> - Get single account
- PUT /api/institution/account/<id> - Update account with validation
- DELETE /api/institution/account/<id> - Delete account with transaction check
- GET /api/categories/<id> - Get single category
- PUT /api/categories/<id> - Update category with FK validation
- DELETE /api/categories/<id> - Delete category with transaction check
- GET /api/transaction/<id> - Get single transaction
- PUT /api/transaction/<id> - Update transaction with validation
- DELETE /api/transaction/<id> - Delete transaction

Frontend Changes:
- Added Edit and Delete buttons to all data tables
- Created edit modals for each entity type
- JavaScript functions for edit/update/delete operations
- Error handling with user-friendly alerts
- Automatic page refresh after successful operations

Referential Integrity:
- Institutions cannot be deleted if they have linked accounts
- Accounts cannot be deleted if they have linked transactions
- Categories cannot be deleted if they have linked transactions
- Clear error messages indicating number of dependent records

Files Modified:
- api/institution/controllers.py - Added detail, update, delete endpoints
- api/institution_account/controllers.py - Added detail, update, delete endpoints
- api/categories/controllers.py - Added detail, update, delete endpoints
- api/transaction/controllers.py - Added detail, update, delete endpoints
- app/transactions/controllers.py - Fixed endpoint name, added data fetching
- app/templates/institution/index.html - Added edit/delete UI
- app/templates/institution_account/index.html - Added edit/delete UI
- app/templates/categories/index.html - Added edit/delete UI
- app/templates/transactions/index.html - Added edit/delete UI
- app/static/js/institution/institution.js - Added CRUD functions
- app/static/js/institution_account/institution_account.js - Added CRUD functions
- app/static/js/categories/categories.js - Added CRUD functions
- app/static/js/transactions/transactions.js - Added CRUD functions