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/discord-gateway/src/modules/ai-moderation/stickerCache.ts

@@ -1,7 +1,7 @@
 import { createChildLogger } from "@bete/shared/logger";
 import { config } from "../../shared/config/config.js";
 import { executeAll, executeGet } from "../../shared/database/drizzle.js";
-import { uploadToTele } from "../attachment-upload/teleUpload.js";
+import { uploadToTele } from "../voice-recording/teleUpload.js";
 
 const logger = createChildLogger("sticker-cache");