Port the neighbor-discovery state machine from mqtt-bridge-implementation-flex,
adapted to this branch's MyMesh (WebConfig members shifted the insertion points;
applied by content).
- Two-stage periodic refresh in loop() driven by mqtt_neighbors_interval:
stage 1 is a zero-hop sendNodeDiscoverReq() (reuses the existing 60s window),
stage 2 (startNeighborDiscover) fires one anon-regions scope query per heard
neighbour, then finishNeighborDiscover() builds the table JSON via
MQTTMessageBuilder::buildNeighborsMessage and hands it to
bridge->requestPublishNeighbors().
- Peer overlay at NEIGHBOR_DISCOVER_PEER_BASE lets scope-query RESPONSE packets
from non-ACL neighbours decrypt: searchPeersByHash prepends heard neighbours
(bounded by MAX_CLIENTS), getPeerSharedSecret derives the secret on the fly,
and onPeerDataRecv routes both overlay-index and ACL-client-that-is-a-neighbour
responses into handleNeighborDiscoverResponse.
- Entries ordered most- to least-useful (recent, then stronger SNR) so the JSON
builder's tail-drop keeps the useful head.
- `discover.scopes` CLI command (manual trigger), with a WITH_MQTT_BRIDGE stub
replying "requires PSRAM" on non-PSRAM builds.
- Reports schedule to the bridge each loop via setNeighborsSchedule().
- Uses ArduinoJson v7 JsonDocument (not deprecated DynamicJsonDocument).
All gated on WITH_MQTT_NEIGHBORS. Reuses the existing MQTTBridge* member.
Verified: T_Beam_S3_Supreme_SX1262_repeater_observer_mqtt builds [SUCCESS].