Kpa-clawbot f9cfad9cd4 fix: update observer last_seen on packet ingestion (#479) ...

## Summary

Related to #463 (partial fix — addresses packet path, status message
path still needs investigation) — Observers incorrectly showing as
offline despite actively forwarding packets.

## Root Cause

Observer `last_seen` was only updated when status topic messages
(`meshcore/<region>/<observer_id>/status`) were received via
`UpsertObserver`. When packets were ingested from an observer, the
observer's `last_seen` was **not** updated — only the `observer_idx` was
resolved for the observation record.

This meant observers with low traffic that published status messages
less frequently than the 10-minute online threshold would appear offline
on the observers page, even though they were clearly alive and
forwarding packets.

## Changes

**`cmd/ingestor/db.go`:**
- Added `stmtUpdateObserverLastSeen` prepared statement: `UPDATE
observers SET last_seen = ? WHERE rowid = ?`
- In `InsertTransmission`, after resolving `observer_idx`, update the
observer's `last_seen` to the packet timestamp
- This ensures any observer actively forwarding traffic stays marked as
online

**`cmd/ingestor/db_test.go`:**
- Added `TestInsertTransmissionUpdatesObserverLastSeen` — verifies that
inserting a packet from an observer updates its `last_seen` from a
backdated value to the packet timestamp

## Performance

The added `UPDATE` is a single-row update by `rowid` (primary key) —
O(1) with no index overhead. It runs once per packet insertion when an
observer is resolved, which was already doing a `SELECT` by `rowid`
anyway. No measurable impact on ingestion throughput.

## Test Results

All existing tests pass:
- `cmd/ingestor`: 26.6s ✅
- `cmd/server`: 3.7s ✅

---------

Co-authored-by: you <you@example.com>

2026-04-01 23:43:47 -07:00

..

ingestor

fix: update observer last_seen on packet ingestion (#479)

2026-04-01 23:43:47 -07:00

server

fix: replace Euclidean distance with haversine in analytics hop distances (#478)

2026-04-01 23:37:01 -07:00