feat(editor): add WSPL JSON round-trip authoring workflow

Closes the WSPL open-format loop with --export-wspl-json /
--import-wspl-json, mirroring the JSON pairs added for
every other novel binary format. All 14 binary formats
added since WOL now have full JSON round-trip authoring.

Each spell round-trips all 18 scalar fields. Four enum-typed
fields emit dual int + name forms so a hand-author can use
either:
  • school     (physical / holy / fire / nature / frost / shadow / arcane)
  • targetType (self / single / cone / aoe-self / line / ground)
  • effectKind (damage / heal / buff / debuff / teleport / summon / dispel)
  • flags      (passive / channeled / ranged / aoe / friendly / hostile / ...)

The flags bitset emits string-array form so a hand-author
can write ["hostile", "aoe"] instead of having to remember
that HostileOnly|AreaOfEffect = 0x110.

Verified byte-identical round-trip on the mage preset (4
spells covering frost / fire / arcane schools and damage /
buff / teleport effects, full flag and effect-value coverage).

Adds 2 flags (544 documented total now).

tools/editor/cli_arg_required.cpp

@@ -58,6 +58,7 @@ const char* const kArgRequired[] = {
     "--export-wskl-json", "--import-wskl-json",
     "--gen-spells", "--gen-spells-mage", "--gen-spells-warrior",
     "--info-wspl", "--validate-wspl",
+    "--export-wspl-json", "--import-wspl-json",
     "--gen-achievements", "--gen-achievements-bandit", "--gen-achievements-meta",
     "--info-wach", "--validate-wach",
     "--gen-weather-temperate", "--gen-weather-arctic",