Rebrand StreamHoard, strip Emergent.sh platform artifacts

- Remove .emergent/ state dir, tracked .gitconfig, @emergentbase/visual-edits
  dep + craco wiring, emergent.sh script/meta tags, PostHog telemetry snippet
- Rename UI/docs branding Kino -> StreamHoard (README, DEPLOY.md, Navbar,
  Login, Register, AdminShowEpisodes, FastAPI title, health check response)
- Rename docker-compose container/network names to streamhoard-*
- Default admin email domain -> admin@streamhoard.local

frontend/src/pages/Register.jsx

@@ -20,7 +20,7 @@ export default function Register() {
     setSubmitting(true);
     try {
       await register(email, password, name);
-      toast.success("Welcome to Kino");
+      toast.success("Welcome to StreamHoard");
       nav("/browse", { replace: true });
     } catch (err) {
       toast.error(err.response?.data?.detail || "Could not register");
@@ -49,7 +49,7 @@ export default function Register() {
       <div className="flex items-center justify-center px-6 md:px-12 py-12">
         <form onSubmit={onSubmit} className="w-full max-w-sm fade-up" data-testid="register-form">
           <Link to="/" className="block mb-12">
-            <span className="font-display text-3xl font-black tracking-tighter text-white">Kino</span>
+            <span className="font-display text-3xl font-black tracking-tighter text-white">StreamHoard</span>
             <span className="text-[#D9381E] text-3xl">.</span>
           </Link>
           <h2 className="font-display text-3xl font-bold tracking-tight text-white">Create account</h2>