Adds a base-URL config field (default = the current value, backward-compatible)
to the 9 adapters that hardcoded their upstream URL — nws, swpc (4 endpoints),
ducting, fires (perimeter+points), firms, avalanche, usgs streams (3 bases),
traffic, satpass/tle_fetch — mirroring the already-compliant roads511 pattern.
Every feed URL is now overridable via config, enforcing the "everything
configurable" rule and making each adapter live-repointable via a config PUT.
Co-authored-by: Matt Johnson <mj@k7zvx.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
