fix: remove MM-146.AC* ticket references from test comments
Removes 6 test comment lines with MM-146.AC* ticket/AC references that
violate CLAUDE.md convention: "No ticket or AC references in source code."
Test function names are self-documenting:
- get_relay_keys_returns_503_when_no_key_provisioned (AC1.3)
- get_relay_keys_returns_200_with_active_key (AC1.1)
- get_relay_keys_returns_most_recently_created_key (AC1.2)
- get_relay_keys_requires_no_authentication (AC1.4)
- external_signer_callback_produces_valid_genesis_op (AC2.1)
- external_signer_callback_error_propagates_as_plc_operation (AC2.2)
Files changed:
- crates/relay/src/routes/get_relay_signing_key.rs: lines 91, 98, 116, 135
- crates/crypto/src/plc.rs: lines 776, 808
Tests: All tests pass (relay get_relay: 4/4, crypto: 44/44)
Formatting: cargo fmt --all --check passes