Codec Issue: 'getValue' function name collision in combined Uplink/Downlink scripts

[WAWXuan]

A getValue function name collision occurs when combining the separated uplink decoder and downlink encoder scripts for platform use (e.g., ChirpStack).

The downlink encoder's getValue (value->key lookup, throws error), likely established around commit dfec81b, overwrites the uplink decoder's getValue (key->value lookup).

This causes uplink decoding to fail (e.g., with "not match in {...}" error) as it calls the incorrect helper function.

Recommendation:
Rename the downlink encoder's getValue helper (e.g., to getKeyFromValue or findKeyByValue) to resolve the conflict in combined scripts.