Fix build: resolve Turbopack client bundle and font issues

- Move EXPENSE_CATEGORIES to ~/lib/expense-categories.ts to break
  server router import chain from client component
- Use inline import() types in trpc/react.tsx to prevent Turbopack
  from including server modules (pg, db) in the client bundle
- Replace next/font/google with system font stacks to fix build
  failures in environments without Google Fonts access

https://claude.ai/code/session_012sqEgNQpx676isepeoX4Mi

src/styles/globals.css

@@ -84,9 +84,9 @@
   --color-input: hsl(var(--input));
   --color-ring: hsl(var(--ring));
 
-  --font-sans: var(--font-sans), sans-serif;
-  --font-heading: var(--font-heading), serif;
-  --font-mono: var(--font-geist-mono), monospace;
+  --font-sans: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
+  --font-heading: ui-serif, Georgia, Cambria, "Times New Roman", Times, serif;
+  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Consolas, "Liberation Mono", Menlo, monospace;
 
   --radius-sm: calc(var(--radius) - 4px);
   --radius-md: calc(var(--radius) - 2px);