Add country dropdown and flags (#28)

* Add country dropdown and flags

* Fix build for country flags

* Improve country select filtering and scoreboard teams

* Fix country select display value

* Fix country select input display

src/shared/countries.ts

@@ -0,0 +1,49 @@
+import { getData, type CountryRecord } from 'country-list';
+
+export interface CountryOption {
+  value: string;
+  label: string;
+}
+
+const baseCountries = getData();
+
+export const countryOptions: CountryOption[] = baseCountries
+  .map((country: CountryRecord) => ({
+    value: country.code,
+    label: country.name,
+  }))
+  .sort((a: CountryOption, b: CountryOption) => a.label.localeCompare(b.label));
+
+const countryByCode = new Map(
+  countryOptions.map((country) => [country.value.toUpperCase(), country.label]),
+);
+const countryByName = new Map(
+  countryOptions.map((country) => [country.label.toLowerCase(), country.value]),
+);
+
+export const resolveCountryCode = (value?: string) => {
+  if (!value) {
+    return '';
+  }
+  const trimmed = value.trim();
+  if (!trimmed) {
+    return '';
+  }
+  const upper = trimmed.toUpperCase();
+  if (countryByCode.has(upper)) {
+    return upper;
+  }
+  const byName = countryByName.get(trimmed.toLowerCase());
+  return byName ?? '';
+};
+
+export const getCountryLabel = (value?: string) => {
+  if (!value) {
+    return '';
+  }
+  const resolved = resolveCountryCode(value);
+  if (!resolved) {
+    return value;
+  }
+  return countryByCode.get(resolved) ?? value;
+};