fix(ui): home bottom nav matches inner screens

Wrap the home-screen NavRail in the same centered max-w-md container + notch-
safe bottom padding that ScreenShell uses, so the pill is identical in width and
position across home and every other screen. Home still drops its redundant Home
tab (5 vs 6) by design.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/components/HomeScreen.tsx

@@ -173,9 +173,15 @@ export function HomeScreen() {
           </div>
         </div>
 
-        {/* bottom nav */}
+        {/* bottom nav — same wrapper as the inner-screen ScreenShell rail
+            (centered max-w-md pill + notch-safe bottom padding) so it looks
+            identical across home and every other screen. */}
+        <div className="shrink-0 px-3 pb-[max(0.5rem,env(safe-area-inset-bottom))]">
+          <div className="mx-auto w-full max-w-md">
             <NavRail bottom />
           </div>
+        </div>
+      </div>
     </main>
   );
 }