Exclude IntelliJ bin/default output from Spotless shell script check

When IntelliJ syncs a Gradle project without build delegation, it copies
processed resources (including reference test shell scripts from the
submodule) into bin/default/. Spotless then finds these copies and
incorrectly flags them for missing license headers, while CI never sees
bin/default/ since it runs bare Gradle.

Add '**/bin/default/**' to the ShellScripts targetExclude, matching the
existing pattern used for other generated/external content.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Simon Dudley <simon.dudley@consensys.net>

Author: siladu

build.gradle

@@ -261,7 +261,7 @@ configure(allprojects - project(':platform')) {
     // Below this line are currently only license header tasks
     format 'ShellScripts', {
       target '**/*.sh'
-      targetExclude '**/src/reference-test/**', '**/src/main/generated/**', '**/src/test/generated/**', '**/src/jmh/generated/**'
+      targetExclude '**/src/reference-test/**', '**/src/main/generated/**', '**/src/test/generated/**', '**/src/jmh/generated/**', '**/bin/default/**'
       trimTrailingWhitespace()
       endWithNewline()