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>

utils/database.py

@@ -636,6 +636,82 @@ def init_db() -> None:
             VALUES ('40069', 'METEOR-M2', NULL, NULL, 1, 1)
         ''')
 
+        # =====================================================================
+        # Ground Station Tables (automated observations, IQ recordings)
+        # =====================================================================
+
+        # Observation profiles — per-satellite capture configuration
+        conn.execute('''
+            CREATE TABLE IF NOT EXISTS observation_profiles (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                norad_id INTEGER UNIQUE NOT NULL,
+                name TEXT NOT NULL,
+                frequency_mhz REAL NOT NULL,
+                decoder_type TEXT NOT NULL DEFAULT 'fm',
+                gain REAL DEFAULT 40.0,
+                bandwidth_hz INTEGER DEFAULT 200000,
+                min_elevation REAL DEFAULT 10.0,
+                enabled BOOLEAN DEFAULT 1,
+                record_iq BOOLEAN DEFAULT 0,
+                iq_sample_rate INTEGER DEFAULT 2400000,
+                created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+            )
+        ''')
+
+        # Observation history — one row per captured pass
+        conn.execute('''
+            CREATE TABLE IF NOT EXISTS ground_station_observations (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                profile_id INTEGER,
+                norad_id INTEGER NOT NULL,
+                satellite TEXT NOT NULL,
+                aos_time TEXT,
+                los_time TEXT,
+                status TEXT DEFAULT 'scheduled',
+                output_path TEXT,
+                packets_decoded INTEGER DEFAULT 0,
+                created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+                FOREIGN KEY (profile_id) REFERENCES observation_profiles(id) ON DELETE SET NULL
+            )
+        ''')
+
+        # Per-observation events (packets decoded, Doppler updates, etc.)
+        conn.execute('''
+            CREATE TABLE IF NOT EXISTS ground_station_events (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                observation_id INTEGER,
+                event_type TEXT NOT NULL,
+                payload_json TEXT,
+                timestamp TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+                FOREIGN KEY (observation_id) REFERENCES ground_station_observations(id) ON DELETE CASCADE
+            )
+        ''')
+
+        # SigMF recordings — one row per IQ recording file pair
+        conn.execute('''
+            CREATE TABLE IF NOT EXISTS sigmf_recordings (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                observation_id INTEGER,
+                sigmf_data_path TEXT NOT NULL,
+                sigmf_meta_path TEXT NOT NULL,
+                size_bytes INTEGER DEFAULT 0,
+                sample_rate INTEGER,
+                center_freq_hz INTEGER,
+                created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+                FOREIGN KEY (observation_id) REFERENCES ground_station_observations(id) ON DELETE SET NULL
+            )
+        ''')
+
+        conn.execute('''
+            CREATE INDEX IF NOT EXISTS idx_gs_observations_norad
+            ON ground_station_observations(norad_id, created_at)
+        ''')
+
+        conn.execute('''
+            CREATE INDEX IF NOT EXISTS idx_gs_events_observation
+            ON ground_station_events(observation_id, timestamp)
+        ''')
+
         logger.info("Database initialized successfully")