df051e8b81
Implements the classify pipeline step with: - Classification rules engine (app/utils/classification_rules.py) with pre-built categories (invoice, contract, receipt, letter, report, bank_statement, tax_document, insurance, payslip) and support for filename patterns, content keywords, and metadata matching rules - Celery task (app/tasks/classify_document.py) that runs as a pipeline step - CRUD API (app/api/classification_rules.py) for managing custom rules - ClassificationRuleModel in app/models.py with migration 027 - Updated pipeline step config_schema and stage mapping - Comprehensive tests for engine, API, and task Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>