Checkpoint: Dispatch Desk

The Dispatch Desk decides how an order is handled, combining nested logic with a switch expression.

Write public static String dispatch(String tier, int weightKg, boolean fragile):

1. If weightKg <= 0, return "rejected: bad weight".
2. Otherwise classify by tier using a switch expression:
   • "standard" → "standard-" + weight class, where weight class is "light" (weight < 5) or "heavy" (5 and above);
   • "express" → "express-" + weight class (same classes);
   • "freight" → "freight-quoted" (weight class ignored);
   • any other tier → "rejected: unknown tier" (regardless of weight).
3. Fragile orders get "+" appended at the very end — but ONLY if the result is not a rejection. dispatch("standard", 3, true) is "standard-light+"; dispatch("gold", 3, false) is "rejected: unknown tier" with no plus.

The boundary at 5 belongs to "heavy". Build the result with a String variable, then decide the suffix once.