Add test case verifying that `forall` returns true for an empty list regardless of predicate, and add two new test files covering runtime errors when `forall` receives a non-boolean-returning function or a non-function argument. Also refactor the `forall` implementation to use logical negation (`!`) instead of explicit `!= true` comparison.
Implement a `forall` method on the Sequence class that takes a predicate function and returns true only if every element in the sequence satisfies the predicate. The method iterates through all elements, returning false immediately upon encountering any element where the predicate does not return exactly true. Includes core library documentation and a test file verifying behavior with numeric comparisons and non-boolean predicate returns.
