feat: redesign homepage layout and fix invite links

- Homepage: Grid-Layout mit 3 Karten (Spiel erstellen, KI, Freunde/Beitreten)
  statt vertikalem Stack mit Dividers
- CreateGame: kompakteres Styling, auf Deutsch, in Primary-Card integriert
- Einladungslink: APP_URL statt hardcoded ches.su in GamePage und CopyLink
- JoinGame: URL-Parsing für beliebige Domains (nicht nur ches.su)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/src/components/home/CreateGame.tsx

@@ -33,35 +33,35 @@ export default function CreateGame() {
   }
 
   return (
-    <form className="form-control" onSubmit={submitCreateGame}>
-      <label className="label cursor-pointer">
-        <span className="label-text">Unlisted/invite-only</span>
-        <input type="checkbox" className="checkbox" name="createUnlisted" id="createUnlisted" />
+    <form className="flex flex-col gap-3" onSubmit={submitCreateGame}>
+      <label className="flex items-center justify-between cursor-pointer">
+        <span className="label-text text-sm">Nur per Einladung</span>
+        <input type="checkbox" className="checkbox checkbox-primary checkbox-sm" name="createUnlisted" id="createUnlisted" />
       </label>
-      <label className="label" htmlFor="createStartingSide">
-        <span className="label-text">Select your side</span>
-      </label>
-      <div className="input-group">
+      <div className="flex gap-2">
         <select
-          className="select select-bordered"
+          className="select select-bordered select-sm flex-1"
           name="createStartingSide"
           id="createStartingSide"
         >
-          <option value="random">Random</option>
-          <option value="white">White</option>
-          <option value="black">Black</option>
+          <option value="random">Zufällig</option>
+          <option value="white">Weiß</option>
+          <option value="black">Schwarz</option>
         </select>
         <button
           className={
-            "btn" +
+            "btn btn-primary btn-sm" +
             (buttonLoading ? " loading" : "") +
-            (!session?.user?.id ? " btn-disabled text-base-content" : "")
+            (!session?.user?.id ? " btn-disabled" : "")
           }
           type="submit"
         >
-          Create
+          Erstellen
         </button>
       </div>
+      {!session?.user?.id && (
+        <p className="text-xs opacity-60">Bitte einloggen um ein Spiel zu erstellen</p>
+      )}
     </form>
   );
 }

client/src/components/home/JoinGame.tsx

@@ -25,8 +25,8 @@ export default function JoinGame() {
 
     setButtonLoading(true);
 
-    if (code.startsWith("ches.su")) {
-      code = "http://" + code;
+    if (!code.startsWith("http") && code.includes("/")) {
+      code = "https://" + code;
     }
     if (code.startsWith("http")) {
       code = new URL(code).pathname.split("/")[1];