Summary of what changed in each file, all confined to the change points shown in the diffs:
ChannelScreen.h — ChannelMessage gains a session-only scope_idx (initialised to 0xFF in the constructor and explicitly reset to 0xFF on SD load, since region is not persisted); addMessage gains a trailing defaulted scope_idx and stores it. The message-list line now renders (Xh)(Xb) Xm, with the byte figure taken from path_len's upper bits for floods and from the_mesh.getNodePrefs()->path_hash_mode + 1 for the 0xFF/0 sentinels. The path overlay shows Route: ... (N-byte) and a new Region: line (name, or (reg unknown), or nothing when unscoped).
MyMesh.h / .cpp — a fixed 28-entry SCOPE_NAMES table, a _scope_keys array precomputed once at the end of begin() via initScopeKeys(), resolveScopeIndex() (matches pkt->transport_codes[0] against the candidates; 0xFF unscoped, 0xFE unmatched), and the public getScopeName() accessor. onChannelMessageRecv resolves the index and passes it to newMsg.
AbstractUITask.h / UITask.h / UITask.cpp — newMsg gains a trailing uint8_t scope_idx = 0xFF; only the channel addMessage call forwards it. DMs and sent echoes keep the default, so they stay unscoped.
MsgFileRecord and the SD save/load format are untouched, so there's no version bump.
pelgraine