refactor(editor): extract README generators into cli_readmes.cpp

Continues the modularization. Moves --gen-zone-readme and
--gen-project-readme into their own translation unit using the
established handle<Family> dispatch pattern. Consolidated the
trailing --out flag parser into a single parseOutFlag helper
(was duplicated between the two handlers).

main.cpp drops 27,736 → 27,445 lines (-291). Behavior unchanged
(verified by re-generating README and PROJECT.md, contents
identical to pre-refactor output).

tools/editor/cli_readmes.hpp

@@ -0,0 +1,16 @@
+#pragma once
+
+namespace wowee {
+namespace editor {
+namespace cli {
+
+// Dispatch the two README auto-generators:
+//   --gen-zone-readme    -> README.md inside a zone
+//   --gen-project-readme -> PROJECT.md at a project root
+//
+// Returns true if matched; outRc holds the exit code.
+bool handleReadmes(int& i, int argc, char** argv, int& outRc);
+
+} // namespace cli
+} // namespace editor
+} // namespace wowee