move the internal preview to canvas (#18930)

* move the internal preview to canvas

* use a helper

* basic readme prep

* .

* .

* transform  better

* byond can't handle icon states of large files...

* move fully to the rust version

* fix typing

* just wtf. NO

* fix the legacy path

* keep it all centralized

* tiny oversight

* unit test rewrite

* rename

* fix bad layering

* fixes a bunch of layering issues

* artifact

* move crash to log_runtime

* missing overlay warning

* why not

code/modules/unit_tests/_unit_tests.dm

@@ -105,7 +105,6 @@
 #include "map_tests.dm"
 #include "mapping.dm"
 #include "material_tests.dm"
-#include "mob_vbo_test.dm"
 // #include "nuke_cinematic.dm" // TODO: This is probably fixed later on
 #include "poster_tests.dm"
 // #include "preferences.dm" // This unit test is missing some other stuff
@@ -121,7 +120,8 @@
 #include "timer_sanity.dm"
 #include "trait_tests.dm"
 #include "unit_test.dm"
-// #include "vore_tests.dm" // FIXME: REWRITE OR FIX THIS
+#include "vbo_tests.dm"
+#include "vore_tests.dm"
 // END_INCLUDE
 #ifdef REFERENCE_TRACKING_DEBUG //Don't try and parse this file if ref tracking isn't turned on. IE: don't parse ref tracking please mr linter
 #include "find_reference_sanity.dm"