feat: enrich military aircraft with ICAO country/force and East Asia model classification

Infer country and military force (PLA, JSDF, ROK, ROC) from ICAO hex
address blocks when the flag field is Unknown. Extract and extend aircraft
model classification to cover East Asian fighters, cargo, recon, and
tanker types with hyphen-normalized matching.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/tests/test_icao_military.py

@@ -0,0 +1,57 @@
+"""Tests for ICAO country enrichment and military type classification."""
+import pytest
+from services.fetchers.military import _enrich_country, _classify_military_type
+
+
+class TestEnrichCountry:
+    def test_china_range(self):
+        assert _enrich_country("780000", "Unknown") == ("China", "PLA")
+
+    def test_japan_range(self):
+        assert _enrich_country("840000", "Unknown") == ("Japan", "JSDF")
+
+    def test_taiwan_range(self):
+        assert _enrich_country("E80000", "Unknown") == ("Taiwan", "ROC")
+
+    def test_south_korea_range(self):
+        assert _enrich_country("700000", "Unknown") == ("South Korea", "ROK")
+
+    def test_out_of_range_unknown_flag(self):
+        assert _enrich_country("A00000", "Unknown") == ("Unknown", "")
+
+    def test_valid_flag_preserved(self):
+        country, force = _enrich_country("780000", "United States")
+        assert country == "United States"
+        assert force == ""
+
+    def test_empty_flag_uses_icao(self):
+        assert _enrich_country("840000", "") == ("Japan", "JSDF")
+
+    def test_military_asset_flag_uses_icao(self):
+        assert _enrich_country("E80000", "Military Asset") == ("Taiwan", "ROC")
+
+    def test_invalid_hex_with_unknown(self):
+        assert _enrich_country("ZZZZ", "Unknown") == ("Unknown", "")
+
+    def test_invalid_hex_with_empty(self):
+        assert _enrich_country("ZZZZ", "") == ("Military Asset", "")
+
+
+class TestClassifyMilitaryType:
+    @pytest.mark.parametrize("model,expected", [
+        ("J-20", "fighter"),
+        ("Y-20", "cargo"),
+        ("KJ-500", "recon"),
+        ("YY-20", "tanker"),
+        ("F-15J", "fighter"),
+        ("FA-50", "fighter"),
+        ("E-2K", "recon"),
+        ("F16", "fighter"),
+        ("C17", "cargo"),
+        ("P8", "recon"),
+        ("H60", "heli"),
+        ("K35", "tanker"),
+        ("Boeing 737", "default"),
+    ])
+    def test_classification(self, model: str, expected: str):
+        assert _classify_military_type(model) == expected