Add live waterfall during pager and sensor decoding via IQ pipeline

Replace rtl_fm/rtl_433 with rtl_sdr for raw IQ capture when available,
enabling a Python IQ processor to compute FFT for the waterfall while
simultaneously feeding decoded data to multimon-ng (pager) or rtl_433
(sensor). Falls back to the legacy pipeline when rtl_sdr is unavailable.

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

utils/dependencies.py

@@ -121,6 +121,15 @@ TOOL_DEPENDENCIES = {
                     'manual': 'https://github.com/EliasOenal/multimon-ng'
                 }
             },
+            'rtl_sdr': {
+                'required': False,
+                'description': 'Raw IQ capture for live waterfall during decoding',
+                'install': {
+                    'apt': 'sudo apt install rtl-sdr',
+                    'brew': 'brew install librtlsdr',
+                    'manual': 'https://osmocom.org/projects/rtl-sdr/wiki'
+                }
+            },
             'rtl_test': {
                 'required': False,
                 'description': 'RTL-SDR device detection',
@@ -143,6 +152,15 @@ TOOL_DEPENDENCIES = {
                     'brew': 'brew install rtl_433',
                     'manual': 'https://github.com/merbanan/rtl_433'
                 }
+            },
+            'rtl_sdr': {
+                'required': False,
+                'description': 'Raw IQ capture for live waterfall during decoding',
+                'install': {
+                    'apt': 'sudo apt install rtl-sdr',
+                    'brew': 'brew install librtlsdr',
+                    'manual': 'https://osmocom.org/projects/rtl-sdr/wiki'
+                }
             }
         }
     },