refactor: replace runtime Intl.DisplayNames with a static CLDR-generated country table

- Add `scripts/generate-countries.mjs` to enumerate all current ISO 3166-1 alpha-2 codes via CLDR and emit `src/lib/countries-data.ts`; retired, exceptionally-reserved, and CLDR-only pseudo codes are explicitly excluded, XK (Kosovo) is kept
- Replace the live `Intl.DisplayNames` calls in `countries.ts` with a direct lookup against the generated `COUNTRY_NAMES` record, eliminating variance between Node/ICU versions
- Build the reverse `nameToCode` map from `COUNTRY_NAMES` entries instead of a double-nested loop over the alphabet
- Fix `countryCodeFromName` to fall through to `ALIASES` for two-letter inputs that aren't valid codes (e.g. `"UK"` → `"GB"`)
- Add `myanmar` / `"myanmar burma"` aliases so the CLDR-style name and the legacy WHOIS variant both resolve to `MM`
- Extend `countries.test.ts` to assert pinned names, XK presence, retired/reserved code exclusion, and `UK` alias behaviour

scripts/generate-countries.mjs

@@ -0,0 +1,64 @@
+// Regenerates src/lib/countries-data.ts from the local runtime's ICU (CLDR) region names.
+// Usage: node scripts/generate-countries.mjs
+import { writeFileSync } from "node:fs";
+
+const dn = new Intl.DisplayNames(["en"], { type: "region" });
+// CLDR also knows reserved, retired and pseudo codes that aren't current ISO 3166-1 countries.
+// Keep only current ISO 3166-1 alpha-2 codes plus XK (Kosovo, the de-facto user-assigned code).
+const EXCLUDE = new Set([
+  "AC",
+  "CP",
+  "DG",
+  "EA",
+  "EU",
+  "EZ",
+  "IC",
+  "TA",
+  "UN", // exceptionally reserved
+  "AN",
+  "BU",
+  "CQ",
+  "CS",
+  "DD",
+  "DY",
+  "FX",
+  "HV",
+  "NH",
+  "RH",
+  "SU",
+  "TP",
+  "VD",
+  "YD",
+  "YU",
+  "ZR", // retired
+  "UK", // reserved for GB; WHOIS "UK" is handled as an alias in countries.ts
+  "QO",
+  "XA",
+  "XB", // CLDR-only pseudo territories
+]);
+
+const entries = [];
+for (let a = 65; a <= 90; a++) {
+  for (let b = 65; b <= 90; b++) {
+    const code = String.fromCharCode(a, b);
+    if (EXCLUDE.has(code)) continue;
+    let name;
+    try {
+      name = dn.of(code);
+    } catch {
+      continue;
+    }
+    if (!name || name === code || name === "Unknown Region") continue;
+    entries.push([code, name]);
+  }
+}
+
+const body = entries.map(([c, n]) => `  ${c}: ${JSON.stringify(n)},`).join("\n");
+writeFileSync(
+  new URL("../src/lib/countries-data.ts", import.meta.url),
+  `// Generated by scripts/generate-countries.mjs from CLDR (Unicode license). Do not edit by hand.\n` +
+    `export const COUNTRY_NAMES: Record<string, string> = {\n${body}\n};\n`,
+);
+console.log(
+  `Wrote ${entries.length} countries (Node ${process.version}, ICU ${process.versions.icu}, CLDR ${process.versions.cldr})`,
+);