fix(endsession): parse arguments with the arg-parser so a slug with -h is no help request, and only the operator starts it

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

lib/parsers/arg-parser.mjs

@@ -1,5 +1,5 @@
 // lib/parsers/arg-parser.mjs
-// Parse $ARGUMENTS strings for the four voyage commands.
+// Parse $ARGUMENTS strings for the seven voyage commands.
 //
 // Each command has its own valid-flag set; passing flags from another command
 // produces an `unknown_flags` array but does not error — the caller decides.
@@ -38,6 +38,11 @@ const FLAG_SCHEMA = {
     valued: ['--profile'],
     aliases: {},
   },
+  trekendsession: {
+    boolean: ['--help'],
+    valued: [],
+    aliases: {},
+  },
 };
 
 /**