MeshCore WebSocket messages still increment Meshtastic nav unread badge

[pskillen]

Type: bug | Area: Navigation / WebSocket unread

Problem

After #279 / PR #323, MeshCore channel messages still sometimes increment the Meshtastic sidebar Messages badge instead of (or in addition to) the MeshCore badge.

Observed while testing (2026-06):

• On the MT messages page, send an MC message to #test → MT nav badge shows 1, MC nav shows none.
• On MC #scotland, send to #test → MC channel + MC nav correct, but MT nav badge can still increment (e.g. 2).

Unread on the correct channel and clearing on channel switch largely work; protocol classification for nav totals is still wrong in some cases.

Likely cause

• WebSocket TextMessage frames may still omit or mis-send protocol on some paths (feeder/API version mismatch), so messageProtocol() in the UI falls back to meshtastic.
• UI fallbacks (original_mc_packet_id, mc_sender_label, mc_sender_candidates) are not always present on the WS payload — see meshflow-api TextMessageWSSerializer.

Related API work: meshflow-api#397.

Deferred rollup (constellation badges, etc.): meshflow-api#396.

Acceptance criteria

• MC message received over WS increments MC nav badge only, never MT (when user is not on MC messages page).
• MT message increments MT nav badge only.
• No stale MT badge requiring full page refresh to clear when only MC traffic arrived.

Notes

Treated as follow-up to #279 (partial fix shipped; good enough for now). Verify against API with WS protocol + original_mc_packet_id deployed.