feat(traps): activation VFX/SFX, explosion effect, and help section

Wire mimic/pit/arrow/laser media on activate, poison/explosion via effects, and document the scene editor and traps in Instructions.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/renderer/shared/traps/mimicActivation.ts

@@ -0,0 +1,6 @@
+/** Реэкспорт для совместимости; канонический модуль — `trapActivation.ts`. */
+export {
+  MIMIC_ACTIVATION_MS,
+  mimicActivationVideoUrl,
+  playMimicActivationSound,
+} from './trapActivation';