@mytec: feat: Phase 3.0 Architecture Refactor ✅

Major refactoring of RFCP backend:
- Modular propagation models (8 models)
- SharedMemoryManager for terrain data
- ProcessPoolExecutor parallel processing
- WebSocket progress streaming
- Building filtering pipeline (351k → 15k)
- 82 unit tests

Performance: Standard preset 38s → 5s (7.6x speedup)

Known issue: Detailed preset timeout (fix in 3.1.0)

backend/tests/test_geometry/test_los.py

@@ -0,0 +1,103 @@
+"""
+Unit tests for line-of-sight and Fresnel zone calculations.
+"""
+
+import sys
+import os
+import math
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..'))
+
+from app.geometry.los import fresnel_radius, check_los_terrain
+
+
+def freq_to_wavelength(freq_mhz):
+    return 300.0 / freq_mhz
+
+
+class TestFresnelRadius:
+    def test_positive_result(self):
+        r = fresnel_radius(500, 500, freq_to_wavelength(1800))
+        assert r > 0
+
+    def test_symmetric(self):
+        wl = freq_to_wavelength(900)
+        r1 = fresnel_radius(300, 700, wl)
+        r2 = fresnel_radius(700, 300, wl)
+        assert abs(r1 - r2) < 0.001
+
+    def test_lower_freq_larger_radius(self):
+        r_high = fresnel_radius(500, 500, freq_to_wavelength(1800))
+        r_low = fresnel_radius(500, 500, freq_to_wavelength(900))
+        assert r_low > r_high
+
+    def test_center_is_maximum(self):
+        """Fresnel radius is largest at the midpoint of the path."""
+        wl = freq_to_wavelength(900)
+        r_center = fresnel_radius(500, 500, wl)
+        r_offset = fresnel_radius(200, 800, wl)
+        assert r_center > r_offset
+
+    def test_known_value(self):
+        """First Fresnel zone radius at midpoint of 1km path at 1GHz ~ 8.66m."""
+        # F1 = sqrt(lambda * d1 * d2 / (d1+d2))
+        # lambda = 0.3m at 1000MHz, d1=d2=500m
+        # F1 = sqrt(0.3 * 500 * 500 / 1000) = sqrt(75) ~ 8.66m
+        r = fresnel_radius(500, 500, freq_to_wavelength(1000))
+        assert 8.0 < r < 9.5
+
+    def test_zero_distance(self):
+        r = fresnel_radius(0, 500, freq_to_wavelength(900))
+        assert r == 0.0
+
+
+class TestCheckLosTerrain:
+    def test_flat_terrain_has_los(self):
+        profile = [
+            {"elevation": 100, "distance": 0},
+            {"elevation": 100, "distance": 250},
+            {"elevation": 100, "distance": 500},
+            {"elevation": 100, "distance": 750},
+            {"elevation": 100, "distance": 1000},
+        ]
+        result = check_los_terrain(profile, tx_height=30, rx_height=1.5)
+        assert result["has_los"] is True
+        assert result["clearance"] > 0
+
+    def test_hill_blocks_los(self):
+        profile = [
+            {"elevation": 100, "distance": 0},
+            {"elevation": 100, "distance": 250},
+            {"elevation": 200, "distance": 500},  # 100m hill
+            {"elevation": 100, "distance": 750},
+            {"elevation": 100, "distance": 1000},
+        ]
+        result = check_los_terrain(profile, tx_height=10, rx_height=1.5)
+        assert result["has_los"] is False
+        assert result["blocked_at"] is not None
+
+    def test_empty_profile(self):
+        result = check_los_terrain([], tx_height=30, rx_height=1.5)
+        assert result["has_los"] is True
+
+    def test_high_antenna_clears_hill(self):
+        profile = [
+            {"elevation": 100, "distance": 0},
+            {"elevation": 110, "distance": 500},
+            {"elevation": 100, "distance": 1000},
+        ]
+        # TX at 150m (100+50), RX at 101.5m. LOS at 500m ≈ 125.75m, terrain=110m → clear
+        result = check_los_terrain(profile, tx_height=50, rx_height=1.5)
+        assert result["has_los"] is True
+
+
+if __name__ == "__main__":
+    for cls in [TestFresnelRadius, TestCheckLosTerrain]:
+        instance = cls()
+        for method_name in [m for m in dir(instance) if m.startswith("test_")]:
+            try:
+                getattr(instance, method_name)()
+                print(f"  PASS  {cls.__name__}.{method_name}")
+            except Exception as e:
+                print(f"  FAIL  {cls.__name__}.{method_name}: {e}")
+    print("\nAll tests completed.")