Adds ~800 new tests (incl. 27 StreamData properties) across 22 modules
that previously had little or no coverage. Highlights:
- Pure utility modules (LogSanitizer, PacketFieldWhitelist,
PacketSanitizer, DeviceParser, CoordinateUtils, BoundsUtils,
ParamUtils, Convert, WeatherUnits) get thorough unit + property
coverage including UTF-8 truncation boundaries, antimeridian
longitude wrap, Haversine symmetry, and unit-conversion inverses.
- JSON view modules (CallsignJSON, ErrorJSON, ChangesetJSON) verified
for envelope shape and error templating.
- Plugs (HealthCheck, RateLimiter, ApiCSRF) exercised for happy-path
and halt paths.
- GenServer modules (RegexCache, CleanupScheduler, DeploymentNotifier)
tested without touching the supervised singleton where possible.
- Drops the orphaned map_live/map_helpers_test.exs whose module name
collided with the new live/shared/coordinate_utils_test.exs.