releaseCodecResources

Release the codec's cached dictionary state.

The codec is the pure-Kotlin org.meshtastic.kzstd library on every target, so there are no native handles to free — ZstdCodec holds only the digested dictionaries (parsed entropy tables + match index) derived from the static shipped dictionary (an optimization, not required state). Calling this is optional; a long-running consumer that wants to reclaim that memory while idle can, and the digests simply rebuild lazily on the next compress/decompress.