refactor: deslop — remove dead botanica preset, extract shared helpers

- Remove dead  theme preset (no CSS, not in DevToolbar)
- Extract  from closure → module-level export in lib/config/index.ts
- Extract  helper in app/[...path]/page.tsx to deduplicate password gate check
- Extract  inner component in app/page.tsx (was 4× inline in minimal/fullbleed/mosaic/split)
- Add 8 unit tests for buildSubpageGrid covering undefined, subset fields, layout fallback, and all fields

app/[...path]/page.tsx

@@ -106,6 +106,21 @@ function toPhotoItems(assets: ImmichAsset[], showExif: boolean): PhotoItem[] {
     });
 }
 
+/**
+ * Returns a PasswordGate element if the slug is protected and not yet
+ * authenticated, otherwise returns null. Centralises the duplicated
+ * cookie-check boilerplate.
+ */
+async function gateIfProtected(slug: string): Promise<React.ReactElement | null> {
+  if (!isProtected(slug)) return null;
+  const cookieStore = await cookies();
+  const getCookie = (name: string) => cookieStore.get(name)?.value;
+  if (isAuthenticated(slug, getCookie)) return null;
+  const subpageData = await immich.getSubpageAlbums(slug);
+  const title = subpageData?.subpage.name ?? slug;
+  return <PasswordGate slug={slug} title={title} />;
+}
+
 export default async function PathPage({ params }: PathPageProps) {
   const { path } = await params;
   const config = getConfig();
@@ -131,15 +146,8 @@ export default async function PathPage({ params }: PathPageProps) {
     const [subpageSlug, albumSlug] = path;
 
     // Password gate for protected subpages
-    if (isProtected(subpageSlug)) {
-      const cookieStore = await cookies();
-      const getCookie = (name: string) => cookieStore.get(name)?.value;
-      if (!isAuthenticated(subpageSlug, getCookie)) {
-        const subpageData = await immich.getSubpageAlbums(subpageSlug);
-        const subpageName = subpageData?.subpage.name ?? subpageSlug;
-        return <PasswordGate slug={subpageSlug} title={subpageName} />;
-      }
-    }
+    const gate = await gateIfProtected(subpageSlug);
+    if (gate) return gate;
 
     const album = await immich.getAlbumBySlug(albumSlug, subpageSlug);
 
@@ -172,15 +180,8 @@ export default async function PathPage({ params }: PathPageProps) {
   // Check if it's a subpage
   if (immich.isSubpageSlug(slug)) {
     // Password gate for protected subpages
-    if (isProtected(slug)) {
-      const cookieStore = await cookies();
-      const getCookie = (name: string) => cookieStore.get(name)?.value;
-      if (!isAuthenticated(slug, getCookie)) {
-        const subpageData = await immich.getSubpageAlbums(slug);
-        const subpageName = subpageData?.subpage.name ?? slug;
-        return <PasswordGate slug={slug} title={subpageName} />;
-      }
-    }
+    const gate = await gateIfProtected(slug);
+    if (gate) return gate;
 
     const result = await immich.getSubpageAlbums(slug);
     if (!result || result.albums.length === 0) {

app/page.tsx

@@ -140,6 +140,27 @@ export default async function HomePage() {
     );
   }
 
+  /** Title + optional subtitle + nav — shared by mosaic, minimal, fullbleed, split. */
+  function HeroTextContent() {
+    return (
+      <>
+        <FadeIn delay={0}>
+          <h1 className="hero__title">{config.siteTitle}</h1>
+        </FadeIn>
+        {config.siteSubtitle && (
+          <FadeIn delay={100}>
+            <p className="hero__subtitle">{config.siteSubtitle}</p>
+          </FadeIn>
+        )}
+        <FadeIn delay={200}>
+          <nav className="hero__nav">
+            <HeroNavLinks subpages={subpages} albums={albums} />
+          </nav>
+        </FadeIn>
+      </>
+    );
+  }
+
   // ── Mosaic: multi-image grid with frosted title overlay ────────
   if (heroStyle === 'mosaic') {
     return (
@@ -161,19 +182,7 @@ export default async function HomePage() {
           ))}
         </div>
         <div className="hero__mosaic-overlay">
-          <FadeIn delay={0}>
-            <h1 className="hero__title">{config.siteTitle}</h1>
-          </FadeIn>
-          {config.siteSubtitle && (
-            <FadeIn delay={100}>
-              <p className="hero__subtitle">{config.siteSubtitle}</p>
-            </FadeIn>
-          )}
-          <FadeIn delay={200}>
-            <nav className="hero__nav">
-              <HeroNavLinks subpages={subpages} albums={albums} />
-            </nav>
-          </FadeIn>
+          <HeroTextContent />
         </div>
       </div>
     );
@@ -184,19 +193,7 @@ export default async function HomePage() {
     return (
       <div className="hero hero--minimal">
         <div className="hero__content">
-          <FadeIn delay={0}>
-            <h1 className="hero__title">{config.siteTitle}</h1>
-          </FadeIn>
-          {config.siteSubtitle && (
-            <FadeIn delay={100}>
-              <p className="hero__subtitle">{config.siteSubtitle}</p>
-            </FadeIn>
-          )}
-          <FadeIn delay={200}>
-            <nav className="hero__nav">
-              <HeroNavLinks subpages={subpages} albums={albums} />
-            </nav>
-          </FadeIn>
+          <HeroTextContent />
         </div>
       </div>
     );
@@ -208,19 +205,7 @@ export default async function HomePage() {
       <div className="hero hero--fullbleed">
         <HeroCarousel images={heroData} />
         <div className="hero__fullbleed-overlay">
-          <FadeIn delay={0}>
-            <h1 className="hero__title">{config.siteTitle}</h1>
-          </FadeIn>
-          {config.siteSubtitle && (
-            <FadeIn delay={100}>
-              <p className="hero__subtitle">{config.siteSubtitle}</p>
-            </FadeIn>
-          )}
-          <FadeIn delay={200}>
-            <nav className="hero__nav">
-              <HeroNavLinks subpages={subpages} albums={albums} />
-            </nav>
-          </FadeIn>
+          <HeroTextContent />
         </div>
       </div>
     );
@@ -232,20 +217,7 @@ export default async function HomePage() {
       {/* ── Left Panel ──────────────────────────────── */}
       <div className="hero__left">
         <div className="hero__content">
-          <FadeIn delay={0}>
-            <h1 className="hero__title">{config.siteTitle}</h1>
-          </FadeIn>
-          {config.siteSubtitle && (
-            <FadeIn delay={100}>
-              <p className="hero__subtitle">{config.siteSubtitle}</p>
-            </FadeIn>
-          )}
-
-          <FadeIn delay={200}>
-            <nav className="hero__nav">
-              <HeroNavLinks subpages={subpages} albums={albums} />
-            </nav>
-          </FadeIn>
+          <HeroTextContent />
         </div>
       </div>