Add numeric router service with unit tests

Add derivative skip regression test for cross-validation runner

Add cross-validation numeric runner

Add cross-validation numeric adapter

Normalize set literals in cross validator

Use deterministic scanner for solution extraction

Add deterministic math structure scanner

Wire Wolfram into numeric validation pipeline

Add SymPy Wolfram CAS arbitration

Add CAS fields to numeric validation reports

Add Wolfram Alpha client with tests

Add Hugging Face API deployment script

Add protected runtime config endpoint

Add private teacher corpus next cases helper

Add tests for private teacher corpus validator

Add tests for teacher quality report generator

Add tests for teacher quality evaluator

Add Supabase Edge Function gateway

Initial BacPilot backend MVP pipeline