test(benchmark): baseline the general-purpose codecs on 128-char input

hexDecode128/hexEncode128 have no denominator in the suite — decode64 can
be read against hexDecodeOurs, but the 64-byte cases had nothing to
compare to. Adds Hex.decode(hex128) and Hex.encode(bytes64) so the
size-enforcing pair's advantage is readable straight off the results.

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

benchmark/src/androidTest/java/com/vitorpamplona/quartz/benchmark/HexBenchmark.kt

@@ -133,6 +133,24 @@ class HexBenchmark {
         r.measureRepeated { Hex.encode128(bytes64) }
     }
 
+    /** The general-purpose decoder on the same 128 chars, for comparison with [hexDecode128]. */
+    @Test
+    fun hexDecodeOurs128() {
+        r.measureRepeated {
+            Hex
+                .decode(hex128)
+        }
+    }
+
+    /** The general-purpose encoder on the same 64 bytes, for comparison with [hexEncode128]. */
+    @Test
+    fun hexEncodeOurs128() {
+        r.measureRepeated {
+            Hex
+                .encode(bytes64)
+        }
+    }
+
     /** The pre-existing two-pass way to safely decode an id, for comparison with [hexDecode64OrNull]. */
     @Test
     fun hexIsHex64ThenDecode() {