Support `$.flags` context values in segment conditions

Support `$.flags..` conditions.

### Acceptance criteria

- The engine dependency is bumped to the version supporting `$.flags` context values.
- `getFlags` passes segments to the engine so identity-less evaluation resolves `$.flags` and `$.environment` conditions.

Start at the getFlags entry point and the engine dependency declaration. Check how segments are passed during identity-less evaluation, then verify that $.flags and $.environment conditions resolve as described in the acceptance criteria.

Written by the indexing model from the issue text.