POST /api/v1/beacon-monitor/measurements accepts one measurement per
integration window from a propmonitor client, authenticated by the
BeaconMonitor token. Records noise floor, signal peak/avg dBFS, SNR,
signal-active-fraction, gain, and frequency for later correlation
against weather and propagation scores.
Beacon UUID must resolve to an approved + on-the-air beacon (404
otherwise — the client drops 404s without retry). Retries with the
same (monitor, beacon, measured_at) are idempotent: a unique index
makes the second insert a 409. Every accepted upload stamps the
monitor's last_seen_at — measurements *are* the heartbeat.
MonitorAuth is a separate plug from the user API-token Auth plug;
monitors are not users. The rate limiter buckets each monitor by id so
retry storms after a 5xx don't burn the shared anon-IP bucket.
Adds bearer-token authenticated REST API at /api/v1 covering every
action a non-admin user can perform on the website: contact + beacon
submission, beacon-monitor management, propagation queries, profile
read/update, and self-service API token issuance/revocation.
Security: SHA-256-hashed bearer tokens (mwp_ prefix, plaintext shown
once at creation), RFC 9457 problem+json error responses, RFC 9651
RateLimit-* headers backed by an ETS bucket (600/min per token,
60/min per anonymous IP, 30/min on /auth/tokens), private-contact
filtering by viewer.
Docs at docs/api/README.md (prose reference) and docs/api/openapi.yaml
(OpenAPI 3.1 spec covering every endpoint, response, and schema).
Tests: 124 new tests across schema, plug, error renderer, rate
limiter, fallback, and every controller. 16/17 API modules at 100%
line coverage; FallbackController at 87.5% (one defmodule line, an
Erlang-cover artifact for action_fallback-only modules).
