新增：导出 / 导入干员调配 (#14)

public/js/ui/clipboard.js

@@ -0,0 +1,35 @@
+// Clipboard helper shared by the room screen (invite code / link) and 干员调配 (导出 / 导入 payloads).
+//
+// Lives here rather than in a screen: `screens/room.js` imports `screens/loadout.js` (the 干员调配 button), so loadout
+// importing the helper back from room would be a cycle.
+
+/**
+ * Copy text to the clipboard (async API with a textarea fallback for insecure contexts).
+ * @param {string} text
+ * @returns {Promise<boolean>}
+ */
+export async function copyText(text) {
+  try {
+    if (globalThis.navigator?.clipboard && globalThis.isSecureContext) {
+      await navigator.clipboard.writeText(text);
+      return true;
+    }
+  } catch { /* fall through */ }
+  try {
+    const ta = document.createElement('textarea');
+    ta.value = text;
+    ta.setAttribute('readonly', '');
+    // 16 px: iOS zooms into smaller focused fields; `readonly` keeps the keyboard away
+    ta.style.cssText = 'position:fixed;left:-9999px;top:0;opacity:0;font-size:16px';
+    document.body.appendChild(ta);
+    ta.select();
+    // iOS Safari ignores select() on a textarea: an explicit range is what it copies (LAN play over http has no
+    // navigator.clipboard, so this path is the one iPhones / iPads take)
+    try { ta.setSelectionRange(0, ta.value.length); } catch { /* ignore */ }
+    const ok = document.execCommand('copy');
+    ta.remove();
+    return ok;
+  } catch {
+    return false;
+  }
+}