fix(gui): align radar parameters to FPGA truth (radar_scene.py)

- Bandwidth 500 MHz -> 20 MHz, sample rate 4 MHz -> 100 MHz (DDC output)
- Range formula: deramped FMCW -> matched-filter c/(2*Fs)*decimation
- Velocity formula: use PRI (167 us) and chirps_per_subframe (16)
- Carrier frequency: 10.525 GHz -> 10.5 GHz per radar_scene.py
- Range per bin: 4.8 m -> 24 m, max range: 307 m -> 1536 m
- Fix simulator target spawn range to match new coverage (50-1400 m)
- Remove dead BANDWIDTH constant, add SAMPLE_RATE to V65 Tk
- All 174 tests pass, ruff clean

9_Firmware/9_3_GUI/v7/workers.py

@@ -334,7 +334,7 @@ class TargetSimulator(QObject):
             self._add_random_target()
 
     def _add_random_target(self):
-        range_m = random.uniform(5000, 40000)
+        range_m = random.uniform(50, 1400)
         azimuth = random.uniform(0, 360)
         velocity = random.uniform(-100, 100)
         elevation = random.uniform(-5, 45)
@@ -368,7 +368,7 @@ class TargetSimulator(QObject):
 
         for t in self._targets:
             new_range = t.range - t.velocity * 0.5
-            if new_range < 500 or new_range > 50000:
+            if new_range < 10 or new_range > 1536:
                 continue  # target exits coverage — drop it
 
             new_vel = max(-150, min(150, t.velocity + random.uniform(-2, 2)))