test(accounts): add a type-only row to the NeedsRehash cost matrix

The existing "old shipping default" row (argon2i, m=8192, t=3) changed type,
memory and time all at once, so it did not independently prove the ArgonType
comparison was load-bearing -- deleting that clause would have left the row
passing on the memory/time checks alone. Add a row that isolates the type
dimension against the current-defaults baseline, alongside the ones that
already isolate memory, iterations and parallelism.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Projects/UOContent.Tests/Tests/Accounting/Security/PasswordProtectionTest.cs

@@ -94,6 +94,7 @@ public class PasswordProtectionTest
     [InlineData("argon2id", 8192, 1, 1, true)]   // right type, stale memory
     [InlineData("argon2id", 16384, 3, 1, true)]  // right type, stale iterations
     [InlineData("argon2id", 16384, 1, 2, true)]  // right type, stale parallelism
+    [InlineData("argon2i", 16384, 1, 1, true)]   // right cost, stale type
     public void Argon2_NeedsRehash_ComparesTypeAndCost(
         string type, int memory, int time, int parallelism, bool expected
     )