feat(pii): Presidio I1+I2 — full recognizer registry + regression tests (98 green)

implemented a feature

metadata engine update

improved bulk chunking

solved merge issues

added 8+ new pii detection models in the classifier, added a new tool for calculating accuracy of the labled pii datasets

added new models

added long files processing

fix: resolve runtime errors and upgrade to Python 3.11

Add email service module and refactor backend code

backend push