refactor(editor): extract remove-* by-index handlers into cli_remove.cpp

Moves the four bounds-checked remove-by-index handlers
(--remove-creature, --remove-object, --remove-quest,
--remove-item) out of main.cpp into a new
cli_remove.{hpp,cpp} module. All four share the same
load-erase-save pattern with index validation and a "what
was removed" report for audit trails. The first three use
their respective editor classes (NpcSpawner, ObjectPlacer,
QuestEditor); --remove-item walks raw nlohmann::json since
items.json doesn't have a dedicated editor class yet.

main.cpp shrinks by 145 lines (6,131 to 5,986).

tools/editor/cli_remove.hpp

@@ -0,0 +1,21 @@
+#pragma once
+
+namespace wowee {
+namespace editor {
+namespace cli {
+
+// Dispatch the remove-* by-index handlers — strip a single
+// entry out of a zone's creatures/objects/quests/items list
+// by 0-based index. All four use bounds-checked load-erase-save
+// and report what was removed for audit trails.
+//   --remove-creature
+//   --remove-object
+//   --remove-quest
+//   --remove-item
+//
+// Returns true if matched; outRc holds the exit code.
+bool handleRemove(int& i, int argc, char** argv, int& outRc);
+
+} // namespace cli
+} // namespace editor
+} // namespace wowee