Replaces reactive bug-specific tests with 4 structural CONTRACTS
that make entire categories of bugs impossible:
1. Serialization Contract (13 parametrized hostile payloads):
Proves SessionStateEncoder NEVER crashes regardless of what
gets injected onto args (datetime, lambda, bytes, inf, nan, etc.)
2. Persistence Contract:
Forces the REAL persist() path by removing PYTEST_CURRENT_TEST guard.
Validates write → read round-trip with poisoned sessions.
3. Production Parity Contract:
Scans ALL GramAddict source for pytest/test-mode divergence guards.
Any unaudited divergence point fails the build. New guards require
explicit justification in KNOWN_DIVERGENCES registry.
4. Import Integrity Contract:
Imports every single GramAddict module to catch syntax errors,
circular imports, and missing dependencies at test time.
This addresses the root systemic failure: tests were running in a
parallel universe where serialization was silently skipped, allowing
a datetime injection to corrupt sessions.json and kill production.
Marc Mintel
cd6cecbe27