refactor: extract Discord.js code from shared services into bot layer

Move terminal.service.ts and prune.service.ts entirely to bot/modules/
since they are Discord-specific. Split lootdrop.service.ts: pure logic
(activity tracking, DB ops, claim) stays in shared/, Discord operations
(message sending, channel interactions) move to bot/modules/economy/
lootdrop.handler.ts. Move effect registry/handlers/types from bot/ to
shared/modules/inventory/ since they contain no Discord.js imports and
are needed by inventory.service.ts in shared.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

shared/modules/inventory/effect.registry.ts

@@ -0,0 +1,41 @@
+import {
+    handleAddXp,
+    handleAddBalance,
+    handleReplyMessage,
+    handleXpBoost,
+    handleTempRole,
+    handleColorRole,
+    handleLootbox
+} from "./effect.handlers";
+import type { EffectHandler, ValidatedEffectPayload } from "./effect.types";
+import { EffectPayloadSchema } from "./effect.types";
+import { UserError } from "@shared/lib/errors";
+import type { Transaction } from "@shared/lib/types";
+
+export const effectHandlers: Record<string, EffectHandler> = {
+    'ADD_XP': handleAddXp,
+    'ADD_BALANCE': handleAddBalance,
+    'REPLY_MESSAGE': handleReplyMessage,
+    'XP_BOOST': handleXpBoost,
+    'TEMP_ROLE': handleTempRole,
+    'COLOR_ROLE': handleColorRole,
+    'LOOTBOX': handleLootbox
+};
+
+export async function validateAndExecuteEffect(
+    effect: unknown,
+    userId: string,
+    tx: Transaction
+) {
+    const result = EffectPayloadSchema.safeParse(effect);
+    if (!result.success) {
+        throw new UserError(`Invalid effect configuration: ${result.error.message}`);
+    }
+
+    const handler = effectHandlers[result.data.type];
+    if (!handler) {
+        throw new UserError(`Unknown effect type: ${result.data.type}`);
+    }
+
+    return handler(userId, result.data, tx);
+}