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`.

pnpm-lock.yaml

@@ -76,9 +76,6 @@ importers:
       pino:
         specifier: ^9.6.0
         version: 9.14.0
-      pino-http:
-        specifier: ^10.3.0
-        version: 10.5.0
       prom-client:
         specifier: ^15.1.3
         version: 15.1.3
@@ -4268,9 +4265,6 @@ packages:
   pino-abstract-transport@3.0.0:
     resolution: {integrity: sha512-wlfUczU+n7Hy/Ha5j9a/gZNy7We5+cXp8YL+X+PG8S0KXxw7n/JXA3c46Y0zQznIJ83URJiwy7Lh56WLokNuxg==}
 
-  pino-http@10.5.0:
-    resolution: {integrity: sha512-hD91XjgaKkSsdn8P7LaebrNzhGTdB086W3pyPihX0EzGPjq5uBJBXo4N5guqNaK6mUjg9aubMF7wDViYek9dRA==}
-
   pino-pretty@13.1.3:
     resolution: {integrity: sha512-ttXRkkOz6WWC95KeY9+xxWL6AtImwbyMHrL1mSwqwW9u+vLp/WIElvHvCSDg0xO/Dzrggz1zv3rN5ovTRVowKg==}
     hasBin: true
@@ -8948,13 +8942,6 @@ snapshots:
     dependencies:
       split2: 4.2.0
 
-  pino-http@10.5.0:
-    dependencies:
-      get-caller-file: 2.0.5
-      pino: 9.14.0
-      pino-std-serializers: 7.1.0
-      process-warning: 5.0.0
-
   pino-pretty@13.1.3:
     dependencies:
       colorette: 2.0.20