Summary

Adds a typed, schema-validated environment configuration module (apps/backend/src/config.ts)
that parses and validates all variables from .env.example at server startup. If any required
variable is missing, empty, contains an unfilled placeholder, or fails a security constraint,
the process exits immediately with a clear human-readable error before the server accepts any
requests. All direct process.env reads across the backend have been replaced with imports
from the new config module.

Closes #255

Type of Change

• Bug fix
• New feature
• Refactor (no functional change)
• UI / Design change
• Tests only
• Documentation
• Infrastructure / DevOps
• Security

What Changed

• Added apps/backend/src/config.ts — validates all env vars at startup with a typed AppConfig interface; exits with a descriptive error on any misconfiguration
• Added apps/backend/src/__tests__/config.test.ts — unit tests covering missing, empty, placeholder, and malformed values for every variable
• Replaced all process.env reads in apps/backend/src/app.ts with config imports
• Replaced all process.env reads in apps/backend/src/server.ts with config imports
• Replaced all process.env reads in apps/backend/src/plugins/prisma.ts with config imports
• Replaced all process.env reads in apps/backend/src/plugins/redis.ts with config imports
• Replaced all process.env reads in apps/backend/src/utils/encryption.ts with config imports
• Replaced all process.env reads in apps/backend/src/routes/auth.ts with config imports