Add Environment Variable Validation to Prevent Misconfiguration

[simarjot0032]

Environment variables are currently accessed without centralized validation, which can lead to runtime errors, unexpected behavior, or silent failures when variables are missing or incorrectly typed.

Problem

• Missing or misconfigured environment variables are not detected early.
• Errors surface only at runtime, making debugging harder.
• No single source of truth exists for required environment variables.
• Type expectations (string, number, boolean) are not enforced.
• Add a proper auto documentation generator for .env.