refactor(editor): extract 9 export handlers + sha256 helper into cli_export.cpp

Moves the report-export handlers (md / csv / html / sha256 /
graphviz) for zone & project audits out of main.cpp:
  --export-zone-summary-md       --export-zone-csv
  --export-zone-checksum         --export-project-checksum
  --validate-project-checksum    --export-zone-html
  --export-project-html          --export-project-md
  --export-quest-graph

Also moves the file-scope wowee_sha256 namespace (the SHA-256
implementation that the checksum exporters use) into the new
module's anonymous namespace — it had no other callers in
main.cpp so no cross-TU coupling needed.

main.cpp drops 13,120 → 12,119 lines (-1,001). Build error
during extraction (missing #include <unordered_set>) caught
and fixed.

CMakeLists.txt

@@ -1321,6 +1321,7 @@ add_executable(wowee_editor
     tools/editor/cli_spawn_audit.cpp
     tools/editor/cli_items.cpp
     tools/editor/cli_extract_info.cpp
+    tools/editor/cli_export.cpp
     tools/editor/editor_app.cpp
     tools/editor/editor_camera.cpp
     tools/editor/editor_viewport.cpp

tools/editor/cli_export.hpp

@@ -0,0 +1,20 @@
+#pragma once
+
+namespace wowee {
+namespace editor {
+namespace cli {
+
+// Dispatch the report-export handlers (md / csv / html / sha256 /
+// graphviz) for zone & project audits:
+//   --export-zone-summary-md       --export-zone-csv
+//   --export-zone-checksum         --export-project-checksum
+//   --validate-project-checksum    --export-zone-html
+//   --export-project-html          --export-project-md
+//   --export-quest-graph
+//
+// Returns true if matched; outRc holds the exit code.
+bool handleExport(int& i, int argc, char** argv, int& outRc);
+
+} // namespace cli
+} // namespace editor
+} // namespace wowee