refactor(editor): table-driven multi-arg flag validation

Collapse main.cpp's hand-written ladder of 28 individual
"if --foo and i+N >= argc, print message, return 1" blocks
into a single loop over kMultiArgRequired (struct of flag,
needed count, synopsis).

main.cpp drops from 246 → 126 lines. Adding a new multi-arg
flag now means appending one row to cli_multi_arg_required.cpp
instead of pasting another six lines into the validation
ladder. Mirrors the kArgRequired pattern that handles
single-arg flags.

tools/editor/cli_multi_arg_required.hpp

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <cstddef>
+
+namespace wowee {
+namespace editor {
+namespace cli {
+
+// Companion to kArgRequired for flags that take MORE than one
+// positional argument. main.cpp uses this list for the early
+// "missing argument" detector — for each entry we check whether
+// argv[i+needed] would run off the end and, if so, print the
+// synopsis and exit 1 instead of silently dropping into the GUI.
+//
+// `needed` is the count of *positional* args after the flag.
+// `synopsis` is the full message shown to the user; it should
+// embed both the flag and the slot list (e.g. "<zoneDir> <x> <y>")
+// so a single std::fprintf reads naturally.
+struct MultiArgFlag {
+    const char* flag;
+    int needed;
+    const char* synopsis;
+};
+
+extern const MultiArgFlag kMultiArgRequired[];
+extern const std::size_t kMultiArgRequiredSize;
+
+} // namespace cli
+} // namespace editor
+} // namespace wowee