Add DMR digital voice, WebSDR, and listening post enhancements

- DMR/P25 digital voice decoder mode with DSD-FME integration
- WebSDR mode with KiwiSDR audio proxy and websocket-client support
- Listening post waterfall/spectrogram visualization and audio streaming
- Dockerfile updates for mbelib and DSD-FME build dependencies
- New tests for DMR, WebSDR, KiwiSDR, waterfall, and signal guess API
- Chart.js date adapter for time-scale axes

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

tests/test_waterfall.py

@@ -0,0 +1,80 @@
+"""Tests for the Waterfall / Spectrogram endpoints."""
+
+from unittest.mock import patch, MagicMock
+import pytest
+
+
+@pytest.fixture
+def auth_client(client):
+    """Client with logged-in session."""
+    with client.session_transaction() as sess:
+        sess['logged_in'] = True
+    return client
+
+
+def test_waterfall_start_no_rtl_power(auth_client):
+    """Start should fail gracefully when rtl_power is not available."""
+    with patch('routes.listening_post.find_rtl_power', return_value=None):
+        resp = auth_client.post('/listening/waterfall/start', json={
+            'start_freq': 88.0,
+            'end_freq': 108.0,
+        })
+        assert resp.status_code == 503
+        data = resp.get_json()
+        assert 'rtl_power' in data['message']
+
+
+def test_waterfall_start_invalid_range(auth_client):
+    """Start should reject end <= start."""
+    with patch('routes.listening_post.find_rtl_power', return_value='/usr/bin/rtl_power'):
+        resp = auth_client.post('/listening/waterfall/start', json={
+            'start_freq': 108.0,
+            'end_freq': 88.0,
+        })
+        assert resp.status_code == 400
+
+
+def test_waterfall_start_success(auth_client):
+    """Start should succeed with mocked rtl_power and device."""
+    with patch('routes.listening_post.find_rtl_power', return_value='/usr/bin/rtl_power'), \
+         patch('routes.listening_post.app_module') as mock_app:
+        mock_app.claim_sdr_device.return_value = None  # No error, claim succeeds
+        resp = auth_client.post('/listening/waterfall/start', json={
+            'start_freq': 88.0,
+            'end_freq': 108.0,
+            'gain': 40,
+            'device': 0,
+        })
+        assert resp.status_code == 200
+        data = resp.get_json()
+        assert data['status'] == 'started'
+
+    # Clean up: stop waterfall
+    import routes.listening_post as lp
+    lp.waterfall_running = False
+
+
+def test_waterfall_stop(auth_client):
+    """Stop should succeed."""
+    resp = auth_client.post('/listening/waterfall/stop')
+    assert resp.status_code == 200
+    data = resp.get_json()
+    assert data['status'] == 'stopped'
+
+
+def test_waterfall_stream_mimetype(auth_client):
+    """Stream should return event-stream content type."""
+    resp = auth_client.get('/listening/waterfall/stream')
+    assert resp.content_type.startswith('text/event-stream')
+
+
+def test_waterfall_start_device_busy(auth_client):
+    """Start should fail when device is in use."""
+    with patch('routes.listening_post.find_rtl_power', return_value='/usr/bin/rtl_power'), \
+         patch('routes.listening_post.app_module') as mock_app:
+        mock_app.claim_sdr_device.return_value = 'SDR device 0 is in use by scanner'
+        resp = auth_client.post('/listening/waterfall/start', json={
+            'start_freq': 88.0,
+            'end_freq': 108.0,
+        })
+        assert resp.status_code == 409