[efiten]

Refs #667 (M1, the first part).

Problem

Observations with direction = 'tx' are packets the observer's own radio sent, published by the MQTT bridge. Nothing in cmd/server or the ingestor's neighbor builder filtered on direction, so these rows counted as receptions.

Two shapes, both seen in a production DB:

• Forwarded flood. A repeater-observer appends its own hash before retransmitting (firmware Mesh.cpp), so the tx copy's path ends on the observer itself, for example tx ["2979","2029"] next to rx ["2979"] for the same transmission.
• Own advert. The observer's own advert goes out with an empty path and no rx copy.

Effects:

• The node detail "Heard By" card listed the observer as having heard itself. On one repeater-observer that was the only row in the card (2,107 packets, no SNR).
• The neighbor graph counted a forwarded advert twice, once from the rx copy and once from the tx copy (originator ↔ path[0]). This happened in both the in-memory build and the ingestor's neighbor_edges builder.

Scale

Last 2,000,000 observations on that DB, about 7.5 days:

• 1,385 tx rows against 1,805,378 rx rows;
• all tx rows have SNR and RSSI NULL;
• every tx row with a non-empty path has an rx row from the same observer for the same transmission.

Change

• StoreObs.isOwnTransmission() (store.go).
• These now skip tx rows:
  • buildDirectHeardIndex (direct_heard.go);
  • phase 1 of the neighbor graph build (neighbor_graph.go);
  • the ingestor's buildAndPersistNeighborEdges SQL, via o.direction IS NOT 'tx' (NULL rows from older bridges still count).

Deliberately not changed

• Reach (node_reach.go). A tx row with path [A, X] from observer X is the only row that shows X received A and forwarded it, because X is absent from the rx copy [A]. There it is valid evidence.
• Home regions (computeNodeHomeRegions). A tx row of the observer's own zero-hop advert counts the observer's own IATA, which is where it is.
• Counters and region filters. These include observation counts, byObserver, packet_count and the SQL region joins. There the effect is double counting of about 0.08% of rows, not a wrong fact. That is left for a follow-up if wanted.
• Existing neighbor_edges rows. The builder is incremental from its watermark, so edges persisted before this change keep their counts. The Heard By card is rebuilt from the store, so it is correct after a restart.

Tests

• Red then green:
  • TestBuildDirectHeardIndex_SkipsOwnTransmissions: before the fix the observer was credited for itself;
  • TestBuildNeighborGraph_SkipsOwnTransmissions: X↔R1 count 2 instead of 1, plus a zero-hop edge from an empty-path tx row;
  • TestNeighborEdgesBuilderSkipsOwnTransmissions: 2 neighbor_edges rows from a single tx observation.
• go vet and go test . pass in cmd/server and cmd/ingestor.

No frontend change. I have not yet checked the "Heard By" card in a browser; that will be on a staging deploy.

[n30nex]

I checked 11e06295 against current master and the firmware's flood-forwarding/TX logging path; I found no production regression in the TX exclusion.

One useful regression-test addition: TestBuildNeighborGraph_SkipsOwnTransmissions checks the X↔R1 count only if that edge is encountered. An entirely empty graph also passes. Explicitly assert that the RX X↔R1 edge exists with count 1, while keeping the prohibited zero-hop-edge assertion. That catches accidentally dropping valid RX evidence along with TX rows.