refactor(editor): extract CLI introspection handlers into cli_introspect.cpp

Moves five self-discovery handlers (--list-commands,
--info-cli-stats, --info-cli-categories, --info-cli-help,
--gen-completion) out of main.cpp into a new
cli_introspect.{hpp,cpp} module. All five auto-discover
commands by parsing printUsage's stdout via tmpfile capture,
so the surface stays self-describing as new flags are added.

Useful for shell completion scripts that re-exec the binary
at completion time, IDE plugins, and 'is there a flag for X?'
search workflows. main.cpp shrinks by 276 lines (2,298 to
2,022). --validate-cli-help stays inline because it needs
direct access to the static-local kArgRequired array.

tools/editor/cli_introspect.hpp

@@ -0,0 +1,23 @@
+#pragma once
+
+namespace wowee {
+namespace editor {
+namespace cli {
+
+// Dispatch the CLI introspection / discoverability handlers —
+// auto-discover commands by parsing printUsage's output so the
+// surface stays self-describing as new flags are added. Useful
+// for shell completion, IDE plugins, and 'is there a flag for X?'
+// search workflows.
+//   --list-commands         flat sorted/deduped flag list
+//   --info-cli-stats        per-category counts (--info-* / --validate-*)
+//   --info-cli-categories   per-category command listing
+//   --info-cli-help <q>     substring search through help text
+//   --gen-completion <bash|zsh>   re-exec'd at completion time
+//
+// Returns true if matched; outRc holds the exit code.
+bool handleIntrospect(int& i, int argc, char** argv, int& outRc);
+
+} // namespace cli
+} // namespace editor
+} // namespace wowee