Dev spawner: RimWorld-style moddable spawn/damage tool (dev mode only)

A side panel (F9, only when developer mode is on) lists entries by category:
animals and plants are auto-populated from their defs (so modded content shows up
automatically), plus action tools. Spawn entries arm a "tool in hand" — left-click
the world to spawn at the cursor (right-click clears); action tools (injure/kill/
infect) apply to the currently selected creature, so you can line up entities and
damage them to compare. Moddable via a new DevToolDef def type: mods add buttons
referencing a code handler kind (spawn-animal/plant/infect/damage/kill) + target,
without touching code. Localized dev.* ru/en. Build + --check-content clean
(13 def types).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Mods/Core/Languages/en/ui.json

@@ -114,6 +114,15 @@
   "settings.volume": "Volume",
   "settings.uiscale": "UI scale",
   "settings.devmode": "Developer mode",
+  "dev.title": "Dev spawner",
+  "dev.hint": "Pick an entry · F9 to hide",
+  "dev.armed": "In hand: {0} · LMB to spawn, RMB to clear",
+  "dev.tools": "Tools",
+  "dev.damage": "Injure selected",
+  "dev.kill": "Kill selected",
+  "dev.infect": "Infect selected",
+  "dev.animals": "Animals",
+  "dev.plants": "Plants",
   "settings.apply": "Apply",
   "settings.back": "Back",
   "pause.title": "Paused",