refactor(telegram): share allowFrom normalization

src/channels/telegram/allow-from.ts

@@ -0,0 +1,11 @@
+export function normalizeTelegramAllowFromEntry(raw: unknown): string {
+  const base = typeof raw === "string" ? raw : typeof raw === "number" ? String(raw) : "";
+  return base
+    .trim()
+    .replace(/^(telegram|tg):/i, "")
+    .trim();
+}
+
+export function isNumericTelegramUserId(raw: string): boolean {
+  return /^\d+$/.test(raw);
+}