refactor(modules): mark DatabaseModule and CryptoModule as global and remove redundant imports

Optimize module imports by marking `DatabaseModule` and `CryptoModule` as global. Remove explicit imports from other modules to reduce duplication and improve maintainability. Update environment variable limits for image and GIF sizes in production.

backend/src/crypto/crypto.module.ts

@@ -1,10 +1,11 @@
-import { Module } from "@nestjs/common";
+import { Global, Module } from "@nestjs/common";
 import { CryptoService } from "./crypto.service";
 import { EncryptionService } from "./services/encryption.service";
 import { HashingService } from "./services/hashing.service";
 import { JwtService } from "./services/jwt.service";
 import { PostQuantumService } from "./services/post-quantum.service";
 
+@Global()
 @Module({
 	providers: [
 		CryptoService,