Consolidated to a single active-request guard with cleanup in finally.
The previous pattern had redundant null-checks across try and catch, and
an always-false check on a controller that was already null. Cancel-on-
new-request is now explicit before creating the new controller.
METEOR-M2 (NORAD 40069) is a weather satellite with LRPT downlink but
was missing from WEATHER_SAT_KEYS, so no capture button appeared in
the pass list. Adds it alongside M2-3 and M2-4.
Replace geocentric.distance().km - 6371 (fixed spherical radius) with
wgs84.subpoint(geocentric).elevation.km in the /position endpoint.
The SSE tracker was already fixed in the Task 1 commit.
Previously currentPos only had lat/lon, so the updateTelemetry fallback
(used before first live position arrives) always showed '---' for
altitude/elevation/azimuth/distance. currentPos now includes all fields
computed from the request observer location. updateTelemetry simplified
to delegate to applyTelemetryPosition.
TLE data was only refreshed once at startup. After each refresh, a new
24-hour timer is now scheduled in a finally block so it fires even on
refresh failure. threading moved to module-level import.
Adds a 'source' param to handleLivePositions. The SSE path ('sse') only
applies lat/lon/altitude/groundTrack since the server-side tracker has
no per-client location. The HTTP poll path ('poll') owns all observer-
relative data and the visible-count badge.
SSE runs server-wide with DEFAULT_LAT/LON defaults of 0,0. Emitting
elevation/azimuth/distance/visible from the tracker produced wrong
values (always visible:False) that overwrote correct data from the
per-client HTTP poll every second.
The HTTP poll (/satellite/position) owns all observer-relative data.
SSE now only emits lat/lon/altitude/groundTrack. Also removes the
unused DEFAULT_LATITUDE/DEFAULT_LONGITUDE import.
