Import march-2020-03-10 from private repo (scrubbed 2026-05-27)

Targets Rec Room 2020.03.10 client (also serves 2020.03.06).

Re-import after adding:
- DorkNet.ClientMod/dorknet-clientmod.json.template — config schema
  the launcher's manifest-driven patcher renders into UserData/.
- tools/build-patcher-zip.ps1 — produces dorknet-clientpatch-{key}.zip
  for v1-march-* Release uploads.
- .github/workflows/release.yml — on tag push publishes both
  dorknet-server-march_2020_03_10-win-x64.zip and
  dorknet-clientpatch-march_2020_03_10.zip as Release assets.

Same scrub rules as december; tools/build-patcher-zip.ps1 added to
the maintainer-side allow-list so it survives.

DorkNet.Server/admin-ui/src/components/Toast.tsx

@@ -0,0 +1,50 @@
+import { createContext, useCallback, useContext, useEffect, useState } from 'react';
+
+type Kind = 'info' | 'success' | 'error';
+interface ToastMsg { id: number; kind: Kind; text: string }
+
+interface Ctx { push: (text: string, kind?: Kind) => void }
+const ToastCtx = createContext<Ctx | null>(null);
+
+export function useToast(): Ctx {
+  const ctx = useContext(ToastCtx);
+  if (!ctx) throw new Error('useToast must be used inside <ToastProvider>');
+  return ctx;
+}
+
+export function ToastProvider({ children }: { children: React.ReactNode }) {
+  const [items, setItems] = useState<ToastMsg[]>([]);
+  const push = useCallback((text: string, kind: Kind = 'info') => {
+    const id = Date.now() + Math.random();
+    setItems(prev => [...prev, { id, kind, text }]);
+    setTimeout(() => setItems(prev => prev.filter(t => t.id !== id)), 4000);
+  }, []);
+
+  return (
+    <ToastCtx.Provider value={{ push }}>
+      {children}
+      <div className="pointer-events-none fixed bottom-6 right-6 z-50 flex flex-col gap-2">
+        {items.map(t => (
+          <ToastItem key={t.id} msg={t} />
+        ))}
+      </div>
+    </ToastCtx.Provider>
+  );
+}
+
+function ToastItem({ msg }: { msg: ToastMsg }) {
+  const [open, setOpen] = useState(false);
+  useEffect(() => { requestAnimationFrame(() => setOpen(true)); }, []);
+  const colors =
+    msg.kind === 'success' ? 'bg-success/15 text-success border-success/30'
+    : msg.kind === 'error' ? 'bg-danger/15 text-danger border-danger/30'
+    : 'bg-ink-800 text-ink-100 border-ink-700';
+  return (
+    <div
+      className={`pointer-events-auto min-w-[240px] max-w-sm rounded-lg border px-3.5 py-2 text-sm shadow-card transition-all duration-200 ${colors} ${open ? 'translate-x-0 opacity-100' : 'translate-x-2 opacity-0'}`}
+      role="status"
+    >
+      {msg.text}
+    </div>
+  );
+}