PairingGuards

Out-of-domain mode-pairing inputs raise rather than returning a wrong number

7/7 passed in 2ms

Test	What it does	Result
test_dark_ceiling	The refusal of a dark probability past a half names the background announcement floor.	✅ pass
test_forward_slots	pairing_click, pairing_sift and pairing_single each refuse an arm transmittance, intensity or dark probability outside its domain.	✅ pass
test_ladder_order	pairing_ladder refuses a decoy at or above the signal, and it and pairing_bases refuse intensity probabilities that do not sum to one.	✅ pass
test_rate_ceiling	pairing_rate refuses a pairing rate above a half, which is what an announcement probability in that slot produces.	✅ pass
test_rate_slots	pairing_rate refuses each of its six arguments outside its domain.	✅ pass
test_short_coherence	pairing_span refuses a coherence time shorter than one round, and an absurd window at the other end.	✅ pass
test_zero_span	pairing_pairs and pairing_drift both refuse a pairing interval of zero rounds.	✅ pass