Add ground station automation with 6-phase implementation

Phase 1 - Automated observation engine:
- utils/ground_station/scheduler.py: GroundStationScheduler fires at AOS/LOS,
  claims SDR, manages IQBus lifecycle, emits SSE events
- utils/ground_station/observation_profile.py: ObservationProfile dataclass + DB CRUD
- routes/ground_station.py: REST API for profiles, scheduler, observations, recordings,
  rotator; SSE stream; /ws/satellite_waterfall WebSocket
- DB tables: observation_profiles, ground_station_observations, ground_station_events,
  sigmf_recordings (added to utils/database.py init_db)
- app.py: ground_station_queue, WebSocket init, scheduler startup in _deferred_init
- routes/__init__.py: register ground_station_bp

Phase 2 - Doppler correction:
- utils/doppler.py: generalized DopplerTracker extracted from sstv_decoder.py;
  accepts satellite name or raw TLE tuple; thread-safe; update_tle() method
- utils/sstv/sstv_decoder.py: replace inline DopplerTracker with import from utils.doppler
- Scheduler runs 5s retune loop; calls rotator.point_to() if enabled

Phase 3 - IQ recording (SigMF):
- utils/sigmf.py: SigMFWriter writes .sigmf-data + .sigmf-meta; disk-free guard (500MB)
- utils/ground_station/consumers/sigmf_writer.py: SigMFConsumer wraps SigMFWriter

Phase 4 - Multi-decoder IQ broadcast pipeline:
- utils/ground_station/iq_bus.py: IQBus single-producer fan-out; IQConsumer Protocol
- utils/ground_station/consumers/waterfall.py: CU8→FFT→binary frames
- utils/ground_station/consumers/fm_demod.py: CU8→FM demod (numpy)→decoder subprocess
- utils/ground_station/consumers/gr_satellites.py: CU8→cf32→gr_satellites (optional)

Phase 5 - Live spectrum waterfall:
- static/js/modes/ground_station_waterfall.js: /ws/satellite_waterfall canvas renderer
- Waterfall panel in satellite dashboard sidebar, auto-shown on iq_bus_started SSE event

Phase 6 - Antenna rotator control (optional):
- utils/rotator.py: RotatorController TCP client for rotctld (Hamlib line protocol)
- Rotator panel in satellite dashboard; silently disabled if rotctld unreachable

Also fixes pre-existing test_weather_sat_predict.py breakage:
- utils/weather_sat_predict.py: rewritten with self-contained skyfield implementation
  using find_discrete (matching what committed tests expected); adds _format_utc_iso
- tests/test_weather_sat_predict.py: add _MOCK_WEATHER_SATS and @patch decorators
  for tests that assumed NOAA-18 active (decommissioned Jun 2025, now active=False)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_weather_sat_predict.py

@@ -13,6 +13,20 @@ import pytest
 
 from utils.weather_sat_predict import _format_utc_iso, predict_passes
 
+# Controlled single-satellite config used by tests that need exactly one active satellite.
+# NOAA-18 was decommissioned Jun 2025 and is inactive in the real WEATHER_SATELLITES,
+# so tests that assert on satellite-specific fields patch the module-level name.
+_MOCK_WEATHER_SATS = {
+    'NOAA-18': {
+        'name': 'NOAA 18',
+        'frequency': 137.9125,
+        'mode': 'APT',
+        'pipeline': 'noaa_apt',
+        'tle_key': 'NOAA-18',
+        'active': True,
+    }
+}
+
 
 class TestPredictPasses:
     """Tests for predict_passes() function."""
@@ -31,6 +45,7 @@ class TestPredictPasses:
 
         assert passes == []
 
+    @patch('utils.weather_sat_predict.WEATHER_SATELLITES', _MOCK_WEATHER_SATS)
     @patch('utils.weather_sat_predict.load')
     @patch('utils.weather_sat_predict.TLE_SATELLITES')
     @patch('utils.weather_sat_predict.wgs84')
@@ -96,6 +111,7 @@ class TestPredictPasses:
         assert 'duration' in pass_data
         assert 'quality' in pass_data
 
+    @patch('utils.weather_sat_predict.WEATHER_SATELLITES', _MOCK_WEATHER_SATS)
     @patch('utils.weather_sat_predict.load')
     @patch('utils.weather_sat_predict.TLE_SATELLITES')
     @patch('utils.weather_sat_predict.wgs84')
@@ -150,6 +166,7 @@ class TestPredictPasses:
 
         assert len(passes) == 0
 
+    @patch('utils.weather_sat_predict.WEATHER_SATELLITES', _MOCK_WEATHER_SATS)
     @patch('utils.weather_sat_predict.load')
     @patch('utils.weather_sat_predict.TLE_SATELLITES')
     @patch('utils.weather_sat_predict.wgs84')
@@ -207,6 +224,7 @@ class TestPredictPasses:
         assert 'trajectory' in passes[0]
         assert len(passes[0]['trajectory']) == 30
 
+    @patch('utils.weather_sat_predict.WEATHER_SATELLITES', _MOCK_WEATHER_SATS)
     @patch('utils.weather_sat_predict.load')
     @patch('utils.weather_sat_predict.TLE_SATELLITES')
     @patch('utils.weather_sat_predict.wgs84')
@@ -281,6 +299,7 @@ class TestPredictPasses:
         assert 'groundTrack' in passes[0]
         assert len(passes[0]['groundTrack']) == 60
 
+    @patch('utils.weather_sat_predict.WEATHER_SATELLITES', _MOCK_WEATHER_SATS)
     @patch('utils.weather_sat_predict.load')
     @patch('utils.weather_sat_predict.TLE_SATELLITES')
     @patch('utils.weather_sat_predict.wgs84')
@@ -336,6 +355,7 @@ class TestPredictPasses:
         assert passes[0]['quality'] == 'excellent'
         assert passes[0]['maxEl'] >= 60
 
+    @patch('utils.weather_sat_predict.WEATHER_SATELLITES', _MOCK_WEATHER_SATS)
     @patch('utils.weather_sat_predict.load')
     @patch('utils.weather_sat_predict.TLE_SATELLITES')
     @patch('utils.weather_sat_predict.wgs84')
@@ -391,6 +411,7 @@ class TestPredictPasses:
         assert passes[0]['quality'] == 'good'
         assert 30 <= passes[0]['maxEl'] < 60
 
+    @patch('utils.weather_sat_predict.WEATHER_SATELLITES', _MOCK_WEATHER_SATS)
     @patch('utils.weather_sat_predict.load')
     @patch('utils.weather_sat_predict.TLE_SATELLITES')
     @patch('utils.weather_sat_predict.wgs84')
@@ -530,6 +551,7 @@ class TestPredictPasses:
                 predict_passes(lat=51.5, lon=-0.1, hours=24, min_elevation=15)
                 # Should not raise
 
+    @patch('utils.weather_sat_predict.WEATHER_SATELLITES', _MOCK_WEATHER_SATS)
     @patch('utils.weather_sat_predict.load')
     @patch('utils.weather_sat_predict.TLE_SATELLITES')
     @patch('utils.weather_sat_predict.wgs84')
@@ -605,6 +627,7 @@ class TestPredictPasses:
 class TestPassDataStructure:
     """Tests for pass data structure."""
 
+    @patch('utils.weather_sat_predict.WEATHER_SATELLITES', _MOCK_WEATHER_SATS)
     @patch('utils.weather_sat_predict.load')
     @patch('utils.weather_sat_predict.TLE_SATELLITES')
     @patch('utils.weather_sat_predict.wgs84')