refactor: improve withTrim identity stability, caching, listener removal, and fix ReceivedChannelItems free payload id bug (#8)

[simpgps]

This PR improves withTrim callback wrappers to resolve issue #8.

Features:

• Caches withTrim wrappers for identical callback/options so repeated calls return the same function.
• Preserves client callback metadata on wrappers so callback registries can add, remove, call, and free them safely.
• Optimizes ClientCallbackSet.remove to support removing via either wrapper reference or the original callback.
• Fixes payload ID bug in ReceivedChannelItems 'free' operation.
• Adds comprehensive regression tests in runtime-typechecking.test.ts covering withTrim wrapper stability, callback sets, and cleanup logic.