Fix weather sat 0dB SNR: increase sample rate to 2.4 MHz for Meteor LRPT

The default 1 MHz sample rate was too low for SatDump's meteor_m2-x_lrpt
pipeline, causing NOSYNC and 0.000dB SNR. Bumped to 2.4 MHz (SatDump
recommendation) and wired up the WEATHER_SAT_SAMPLE_RATE config value
so it actually gets passed to decoder.start() from both the auto-scheduler
and manual start route.

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

routes/weather_sat.py

@@ -18,6 +18,7 @@ from utils.weather_sat import (
     is_weather_sat_available,
     CaptureProgress,
     WEATHER_SATELLITES,
+    DEFAULT_SAMPLE_RATE,
 )
 
 logger = get_logger('intercept.weather_sat')
@@ -164,6 +165,7 @@ def start_capture():
         satellite=satellite,
         device_index=device_index,
         gain=gain,
+        sample_rate=DEFAULT_SAMPLE_RATE,
         bias_t=bias_t,
     )
 
@@ -563,26 +565,26 @@ def enable_schedule():
             'message': 'Invalid parameter value'
         }), 400
 
-    scheduler = get_weather_sat_scheduler()
-    scheduler.set_callbacks(_progress_callback, _scheduler_event_callback)
-
-    try:
-        result = scheduler.enable(
-            lat=lat,
-            lon=lon,
-            min_elevation=min_elev,
-            device=device,
-            gain=gain_val,
-            bias_t=bool(data.get('bias_t', False)),
-        )
-    except Exception as e:
-        logger.exception("Failed to enable weather sat scheduler")
-        return jsonify({
-            'status': 'error',
-            'message': 'Failed to enable scheduler'
-        }), 500
-
-    return jsonify({'status': 'ok', **result})
+    scheduler = get_weather_sat_scheduler()
+    scheduler.set_callbacks(_progress_callback, _scheduler_event_callback)
+
+    try:
+        result = scheduler.enable(
+            lat=lat,
+            lon=lon,
+            min_elevation=min_elev,
+            device=device,
+            gain=gain_val,
+            bias_t=bool(data.get('bias_t', False)),
+        )
+    except Exception as e:
+        logger.exception("Failed to enable weather sat scheduler")
+        return jsonify({
+            'status': 'error',
+            'message': 'Failed to enable scheduler'
+        }), 500
+
+    return jsonify({'status': 'ok', **result})
 
 
 @weather_sat_bp.route('/schedule/disable', methods=['POST'])