chore: update codeowners (#3292)

* chore: update codeowners for project:deletion

* chore: update codeowners for project:mcp-ui

* chore: add catch-all to codeowners

Author: stephl3

.github/CODEOWNERS

@@ -1,7 +1,18 @@
 # project:chat
 chat/ @mongodb/lg-chat
 
+# project:deletion
+packages/wizard @mongodb/lg-deletion
+
+# project:mcp-ui
+apps/mcp-ui-app @mongodb/lg-mcp-ui
+mcp-ui @mongodb/lg-mcp-ui
+
 # project:time-input
 packages/date-picker @mongodb/lg-time-input
 packages/date-utils @mongodb/lg-time-input
 packages/time-input @mongodb/lg-time-input
+
+# catch-all rule: any file not matching a more specific rule below
+# will be assigned to @leafygreen-ui-maintainers
+* @mongodb/leafygreen-ui-maintainers