Handle `any` correctly — it is not a type but a directive that disables type checking. Substitute by position (assignee → `unknown`, assigned → `never`). Two narrow exceptions: a generic constraint, and a callback parameter caught in a bivariant position between two fixed, irresolvable function-type constraints — both declared with an inline eslint-disable. Also covers the `any` that is never written down: a precise signature fed `any` at every call site, which no lint rule and no compiler check can report.
