EnvelopeCodec message layer; scripts are thin business-API wrappers

docs/RE_DART_FINDINGS.md

@@ -188,8 +188,14 @@ marker model is kept for the unverified Bluetooth path.
    failures keep accumulating ("receive incomplete data").
 
 So requests are `S1 || transform(S2)` (split at the computable header
-length) while responses are `s || 0x58 || transform(tail)` (split at the
-second `0x58` marker). Both halves share the one additive stream.
+length); live socket replies use the identical framing and split
+(`decrypt_wire` locates the header at the 2nd comma — no ids needed up
+front). Both halves share the one additive stream.
+
+Library shape: `protocol/messages.py:EnvelopeCodec` owns the bytes
+(`encode`/`decode` under one device key); `device_local`,
+`battery` and `power` implement the business calls on top; `scripts/`
+are thin CLI wrappers over those calls.
 
 Live corroboration (2026-10-15, PCAPdroid capture of the working app): a
 request frame opens with the ASCII header