chore(mollifier): drop fuzz tests to keep phase-1 PR focused

drainer.fuzz.test.ts and evaluateTrip.fuzz.test.ts are valuable as
ongoing property checks but aren't load-bearing for the phase-1 review.
Moving them to a follow-up keeps this PR smaller without losing coverage
of the production paths (buffer.test.ts and drainer.test.ts together
cover the contract surface).

Author: d-cs