Opt Big Shoulders out of automatic fallback-metrics adjustment

Next's fallback-metrics table has no entry for this (newer, merged
variable-font) family name, so the CLS-reducing fallback override it
tries to generate always fails with a build warning. Correctly
suppresses it under webpack; Turbopack (this project's default
builder) doesn't yet honor the flag the same way, so the warning
still prints there today, but the setting is still the semantically
correct declaration of intent and forward-compatible.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012hQoM3jJT1Lx7CMTciMzvD

app/layout.tsx

@@ -7,6 +7,11 @@ const bigShoulders = Big_Shoulders({
   variable: "--font-big-shoulders",
   weight: ["700", "900"],
   subsets: ["latin"],
+  // Next's fallback-metrics table has no entry for this (newer, merged
+  // variable-font) family name, so the automatic CLS-reducing fallback
+  // override it would otherwise generate always fails with a build
+  // warning — opt out instead of leaving that warning unresolved.
+  adjustFontFallback: false,
 });
 
 const spaceGrotesk = Space_Grotesk({