Extract season overview/workflow cards and add sponsor seed data

Splits AdminSeasonsView into AdminSeasonOverviewCard and AdminSeasonWorkflowCard
for cleaner separation of concerns. Adds SeedSponsorsBootstrapper with demo
sponsor SVG assets and extends SeedCatalog with sponsor seed entries.

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

Backend/Data/SeedCatalog.cs

@@ -7,6 +7,7 @@ internal sealed record CandidateSeed(string CategorySlug, string DisplayName, st
 internal sealed record WinnerSeed(int Year, string CategorySlug, string DisplayName, string ChannelSlug, string Platform);
 internal sealed record SiteFaqSeed(string Question, string Answer);
 internal sealed record SiteSocialSeed(string Label, string Platform, string Url, string Icon);
+internal sealed record SponsorSeed(string Name, string WebsiteUrl, string LogoUrl, string Description, string Tier, int SortOrder);
 
 internal static class SeedCatalog
 {
@@ -141,4 +142,43 @@ Partner werden im Rahmen der Show und auf den öffentlichen Kontaktflächen gena
         new(2023, "community-liebling-rising-star", "Sora Blau", "@sorablau", "YouTube"),
         new(2023, "best-collab-duo-rising-star", "Yuki & Melo", "@yukistern", "Twitch"),
     ];
+
+    internal static readonly SponsorSeed[] DemoSponsorSeeds =
+    [
+        new(
+            "HoshiForge Studio",
+            "https://hoshiforge.example",
+            "/demo/sponsors/hoshiforge-studio.svg",
+            "Branding-, Overlay- und Debuet-Visuals fuer VTuber-Projekte und Community-Events.",
+            "Presenting Sponsor",
+            10),
+        new(
+            "NekoPixel Energy",
+            "https://nekopixel.example",
+            "/demo/sponsors/nekopixel-energy.svg",
+            "Community-fokussierter Drink-Partner fuer lange Showabende, Watchpartys und Creator-Collabs.",
+            "Gold Partner",
+            20),
+        new(
+            "PrismLoop Audio",
+            "https://prismloop.example",
+            "/demo/sponsors/prismloop-audio.svg",
+            "Audio-Tools, Intro-Packs und Stream-Sounddesign fuer Live-Shows und Highlight-Clips.",
+            "Gold Partner",
+            30),
+        new(
+            "CloudBeacon Hosting",
+            "https://cloudbeacon.example",
+            "/demo/sponsors/cloudbeacon-hosting.svg",
+            "Skalierbares Hosting fuer Voting, Landingpages und Event-Traffic rund um Showtage.",
+            "Tech Partner",
+            40),
+        new(
+            "ChibiCanvas Market",
+            "https://chibicanvas.example",
+            "/demo/sponsors/chibicanvas-market.svg",
+            "Merch-, Sticker- und Artist-Marketplace mit Fokus auf VTuber, Emotes und Fanartikel.",
+            "Community Partner",
+            50),
+    ];
 }