fix: add BER to airports.py so scans include Berlin Brandenburg

OpenFlights dataset predates BER's 2020 opening. The patch already
existed in api_server.py for the search UI, but scan_processor.py
uses airports.py directly, so Germany scans silently skipped BER.

Added _MISSING_AIRPORTS to airports.py, patched both
get_airports_for_country() and _all_airports_by_iata() to inject
the extras, making BER available to scans and lookups.

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

flight-comparator/airports.py

@@ -69,6 +69,13 @@ COUNTRY_NAME_TO_ISO = {
 }
 
 
+# Airports missing from the OpenFlights dataset (opened or renamed after dataset was last updated).
+# Keyed by ISO country code; dicts match the airports_by_country.json schema (iata/name/city/icao).
+_MISSING_AIRPORTS: dict[str, list[dict]] = {
+    'DE': [{'iata': 'BER', 'name': 'Berlin Brandenburg Airport', 'city': 'Berlin', 'icao': 'EDDB'}],
+}
+
+
 def country_name_to_iso_code(country_name: str) -> Optional[str]:
     """
     Convert country name to ISO 2-letter code.
@@ -197,7 +204,12 @@ def get_airports_for_country(country_code: str) -> list[dict]:
             f"Available codes (sample): {', '.join(available)}..."
         )
 
-    return airports_by_country[country_code]
+    result = list(airports_by_country[country_code])
+    existing_iatas = {a['iata'] for a in result}
+    for extra in _MISSING_AIRPORTS.get(country_code, []):
+        if extra['iata'] not in existing_iatas:
+            result.append(extra)
+    return result
 
 
 def resolve_airport_list(country: Optional[str], from_airports: Optional[str]) -> list[dict]:
@@ -233,11 +245,16 @@ def _all_airports_by_iata() -> dict:
         download_and_build_airport_data()
     with open(AIRPORTS_JSON_PATH, 'r', encoding='utf-8') as f:
         airports_by_country = json.load(f)
-    return {
+    result = {
         a['iata']: a
         for airports in airports_by_country.values()
         for a in airports
     }
+    for extras in _MISSING_AIRPORTS.values():
+        for extra in extras:
+            if extra['iata'] not in result:
+                result[extra['iata']] = extra
+    return result
 
 
 def lookup_airport(iata: str) -> dict | None: