feat: import existing gitea customizations from mvpsm

Themes (dark/light), logo, favicon, and template overrides.

templates/home.tmpl

@@ -0,0 +1,37 @@
+{{template "base/head" .}}
+<style>
+  .page-content.home {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    min-height: calc(100vh - 200px);
+    padding: 2rem 1rem;
+  }
+  .home .center {
+    text-align: center;
+  }
+  .home .mgit-logo-text {
+    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
+    font-weight: 700;
+    font-size: 4rem;
+    letter-spacing: -0.05em;
+    color: var(--color-primary, #2563eb);
+    margin: 0;
+    line-height: 1.2;
+  }
+  .home .mgit-logo-text::before {
+    content: '';
+    display: block;
+    width: 80px;
+    height: 4px;
+    background: linear-gradient(90deg, #2563eb 0%, #1e40af 100%);
+    margin: 0 auto 1.5rem;
+    border-radius: 2px;
+  }
+</style>
+<div role="main" aria-label="{{if .IsSigned}}{{ctx.Locale.Tr "dashboard"}}{{else}}{{ctx.Locale.Tr "home_title"}}{{end}}" class="page-content home">
+	<div class="center">
+		<div class="mgit-logo-text">mGit</div>
+	</div>
+</div>
+{{template "base/footer" .}}