Code-health ratchet: plugins/platforms/matrix/adapter.py was 3308 > 3278 and
tests/gateway/test_matrix.py 3310 > 3245 (both over the 2,000-line target, so
they may only shrink vs main).
- Move the existing _CryptoStateStore OlmMachine state-store shim (byte-identical)
into the new topical sibling plugins/platforms/matrix/adapter_crypto.py; the
one call site in _connect_setup_e2ee late-imports it. No facade re-export.
- Move this stack's encrypted-drop warning tests (and their _cryptoless_client
helper) into tests/gateway/test_matrix_encrypted_drop_warning.py.
2efd6961f7