cache:pool:prune fails with a fatal error when cache tracing is enabled (the default) and a prunable pool is configured - typically a DB-backed app cache. Since the command is usually run on a schedule, it surfaces as a recurring failure of the cleanup job rather than an interactive error.

The cause: Symfony tags prunable pools, and when a pool is wrapped for tracing, that tag is transferred onto TraceableCachePool. Symfony's pruner then selects the decorator and calls prune() on it - a method the decorator did not implement, resulting in Call to undefined method ...TraceableCachePool::prune().

The fix follows Symfony's own TraceableAdapter: TraceableCachePool now implements PruneableInterface and delegates prune() to the wrapped pool, returning false when that pool is not prunable. The tag-aware and namespaced variants inherit the behaviour.

Two tests cover it - delegation to a prunable pool, and false for a non-prunable one. Full suite passes, PHPStan level 10 clean.

Fixes #56.