feat: add East Asia news sources and improve geocoding for Taiwan contingency

Add 5 East Asia-focused RSS feeds (FocusTaiwan, Kyodo, SCMP, The Diplomat,
Stars and Stripes) and 22 geographic keywords (Taiwan Strait, South/East
China Sea, Okinawa, Guam, military bases, etc.) to improve coverage of
Taiwan contingency scenarios.

Refactor keyword matching into a pure _resolve_coords() function with
longest-match-first sorting so specific locations like "Taiwan Strait"
are not absorbed by generic "Taiwan".

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

backend/tests/test_news_keywords.py

@@ -0,0 +1,102 @@
+"""Regression tests for news geocoding keywords and feed configuration."""
+import json
+from pathlib import Path
+
+import pytest
+
+from services.fetchers.news import _resolve_coords
+from services.news_feed_config import DEFAULT_FEEDS
+
+
+CONFIG_PATH = Path(__file__).parent.parent / "config" / "news_feeds.json"
+
+
+# -- Keyword resolution: East Asia specific locations --------------------------
+
+class TestResolveCoords:
+    """_resolve_coords should prefer longer (more specific) keywords."""
+
+    def test_taiwan_strait_not_absorbed_by_taiwan(self):
+        result = _resolve_coords("tensions in the taiwan strait")
+        assert result == (24.0, 119.5)
+
+    def test_south_china_sea_not_absorbed_by_china(self):
+        result = _resolve_coords("south china sea patrol")
+        assert result == (15.0, 115.0)
+
+    def test_east_china_sea(self):
+        result = _resolve_coords("east china sea tensions")
+        assert result == (28.0, 125.0)
+
+    def test_philippine_sea(self):
+        result = _resolve_coords("philippine sea exercises")
+        assert result == (20.0, 130.0)
+
+    def test_generic_china_still_works(self):
+        result = _resolve_coords("china deploys forces")
+        assert result == (35.861, 104.195)
+
+    def test_generic_taiwan_still_works(self):
+        result = _resolve_coords("taiwan elections")
+        assert result == (23.697, 120.960)
+
+    def test_taipei(self):
+        result = _resolve_coords("protests in taipei")
+        assert result == (25.033, 121.565)
+
+    def test_okinawa(self):
+        result = _resolve_coords("okinawa base expansion")
+        assert result == (26.334, 127.800)
+
+    # -- Existing inclusion-relationship regressions ---------------------------
+
+    def test_new_delhi_not_absorbed_by_delhi(self):
+        result = _resolve_coords("new delhi summit")
+        assert result == (28.613, 77.209)
+
+    def test_south_america_not_absorbed_by_america(self):
+        result = _resolve_coords("south america trade deal")
+        assert result == (-14.200, -51.900)
+
+    def test_north_korea_not_absorbed_by_south_korea(self):
+        result = _resolve_coords("north korea missile launch")
+        assert result == (40.339, 127.510)
+
+    # -- Space-padded keywords -------------------------------------------------
+
+    def test_us_with_spaces(self):
+        result = _resolve_coords("the us military")
+        assert result == (38.907, -77.036)
+
+    def test_uk_with_spaces(self):
+        result = _resolve_coords("visit the uk soon")
+        assert result == (55.378, -3.435)
+
+    # -- No match --------------------------------------------------------------
+
+    def test_no_match_returns_none(self):
+        result = _resolve_coords("unknown location xyz")
+        assert result is None
+
+
+# -- Feed configuration consistency -------------------------------------------
+
+class TestFeedConfig:
+    """DEFAULT_FEEDS and news_feeds.json must stay in sync."""
+
+    def test_default_feeds_match_json(self):
+        data = json.loads(CONFIG_PATH.read_text(encoding="utf-8"))
+        json_feeds = data["feeds"]
+
+        def normalize(feeds):
+            return sorted(
+                [{"name": f["name"], "url": f["url"], "weight": f["weight"]} for f in feeds],
+                key=lambda f: f["name"],
+            )
+
+        assert normalize(DEFAULT_FEEDS) == normalize(json_feeds)
+
+    def test_new_east_asia_feeds_present(self):
+        names = {f["name"] for f in DEFAULT_FEEDS}
+        expected = {"FocusTaiwan", "Kyodo", "SCMP", "The Diplomat", "Stars and Stripes"}
+        assert expected.issubset(names)