feat: hero card layout in all pills, cache-while-loading, logo splash screen

- Every pill (F1, Tech, AI, Cloud, HomeLab…) now shows the same hero card
  layout as "All" — first story is the big featured card, rest follow as rows
- "All" retains its full multi-section front page (US / Tech / AI / Sport…)
- Topic pill headers use the pill name instead of "TOP STORIES"
- filteredStories now falls back to cached SwiftData rows while loading, so
  switching to F1 or Tech shows cached cards instantly instead of a blank list
- Logo splash screen (3 pill bars + jarvis wordmark) shows on launch and fades
  out after setup completes; minimum 1.3 s so it's always readable
- JarvisWordmark moved to Theme.swift so SplashView and feed can share it

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

Jarvis/Views/Shared/Theme.swift

@@ -264,6 +264,19 @@ extension StorySummary {
     }
 }
 
+// MARK: - Wordmark
+
+struct JarvisWordmark: View {
+    var size: CGFloat = 30
+    private var font: Font { .custom("Courier New", size: size).bold() }
+    var body: some View {
+        HStack(spacing: 0) {
+            Text("j").font(font).foregroundStyle(Palette.orange)
+            Text("arvis").font(font).foregroundStyle(.white)
+        }
+    }
+}
+
 // MARK: - News sections (the "All" front page)
 //
 // Groups the firehose into Apple/Google-News-style sections. A story lands in