refactor: break monorepo into 3 standalone services (gateway, backend, frontend)

- Remove pnpm workspace, moon repo, and all monorepo tooling
- Delete packages/shared/, embed shared code directly into each service
- Copy packages/shared/src/* -> services/backend/src/shared/ and services/discord-gateway/src/shared/
- Replace all @bete/shared imports with @/shared/ path alias
- Remove @bete/shared workspace dependency from both services
- Update root package.json scripts from --filter to --prefix
- Rewrite Dockerfiles to build each service standalone
- Clean up biome.json, .gitignore, remove root drizzle.config.ts

services/discord-gateway/src/modules/ai-moderation/simpleFallback.ts

@@ -6,7 +6,7 @@
  * Step 2: Real analysis text (only if not clean).
  * Extracted from moderationOrchestrator.ts.
  */
-import { createChildLogger } from "@bete/shared/logger";
+import { createChildLogger } from "@/shared/logger/index";
 import type {
   AnalysisResult,
   MessageRecord,