refactor(shared): centralize configuration and types

Migrate configuration validation and core moderation types from individual services to the `@bete/shared` package to ensure consistency across the monorepo.

- Move `AppConfig` and moderation-related interfaces to `packages/shared`.
- Replace service-specific Zod schemas with the centralized shared configuration.
- Refactor `services/backend` and `services/discord-gateway` to consume shared config and types.
- Remove redundant type definitions and local configuration logic in services.
- Update `packages/shared` exports to include new `config` and `moderation-types` modules.
- Clean up unused files and deprecated utility functions in `packages/shared`.

services/backend/src/ws/broadcast.ts

@@ -1,7 +1,7 @@
 /**
- * Global broadcast functions for WebSocket events.
+ * Broadcast functions for WebSocket events.
  *
- * These are assigned by ws/server.ts when the WebSocket server initializes.
+ * These are injected by ws/server.ts when the WebSocket server initializes.
  * Other modules call them to push real-time events to connected frontend clients.
  *
  * Usage:
@@ -13,38 +13,48 @@ type BroadcastFn = (data: unknown) => void;
 type BroadcastRawFn = (type: string, data: unknown) => void;
 type BroadcastBinaryFn = (data: Buffer) => void;
 
-declare global {
-  // biome-ignore lint/suspicious/noAssignInExpressions: intentional global broadcast registry
-  var __broadcastFns:
-    | {
-        messageCreated: BroadcastFn;
-        messageUpdated: BroadcastFn;
-        messageDeleted: BroadcastFn;
-        attachmentUploaded: BroadcastFn;
-        raw: BroadcastRawFn;
-        binary: BroadcastBinaryFn;
-      }
-    | undefined;
+export interface BroadcastFunctions {
+  messageCreated: BroadcastFn;
+  messageUpdated: BroadcastFn;
+  messageDeleted: BroadcastFn;
+  attachmentUploaded: BroadcastFn;
+  raw: BroadcastRawFn;
+  binary: BroadcastBinaryFn;
 }
 
 const noop: BroadcastFn = () => {};
 const noopRaw: BroadcastRawFn = () => {};
 const noopBinary: BroadcastBinaryFn = () => {};
 
+let _fns: BroadcastFunctions | null = null;
+
+/**
+ * Inject broadcast functions from the WebSocket server initializer.
+ * Must be called once during server startup before any broadcast is used.
+ */
+export function setBroadcastFunctions(fns: BroadcastFunctions): void {
+  _fns = fns;
+}
+
+/** Clear injected functions (used during cleanup). */
+export function clearBroadcastFunctions(): void {
+  _fns = null;
+}
+
 export const broadcastMessageCreated: BroadcastFn = (data) =>
-  (globalThis.__broadcastFns?.messageCreated ?? noop)(data);
+  (_fns?.messageCreated ?? noop)(data);
 
 export const broadcastMessageUpdated: BroadcastFn = (data) =>
-  (globalThis.__broadcastFns?.messageUpdated ?? noop)(data);
+  (_fns?.messageUpdated ?? noop)(data);
 
 export const broadcastMessageDeleted: BroadcastFn = (data) =>
-  (globalThis.__broadcastFns?.messageDeleted ?? noop)(data);
+  (_fns?.messageDeleted ?? noop)(data);
 
 export const broadcastAttachmentUploaded: BroadcastFn = (data) =>
-  (globalThis.__broadcastFns?.attachmentUploaded ?? noop)(data);
+  (_fns?.attachmentUploaded ?? noop)(data);
 
 export const broadcastRaw: BroadcastRawFn = (type, data) =>
-  (globalThis.__broadcastFns?.raw ?? noopRaw)(type, data);
+  (_fns?.raw ?? noopRaw)(type, data);
 
 export const broadcastBinary: BroadcastBinaryFn = (data) =>
-  (globalThis.__broadcastFns?.binary ?? noopBinary)(data);
+  (_fns?.binary ?? noopBinary)(data);