fix: address primitive obsession with typed value objects

[Mathious6]

Why?

Our CLI currently uses many primitive types (String, i64, etc.) to represent domain concepts like client numbers, account IDs, and quote lengths. This makes validation scattered and fragile, increasing the risk of runtime errors and invalid user input slipping through. As suggested by Refactoring Guru – Primitive Obsession, defining small, dedicated value types improves:

• Type safety
• Input validation at construction
• Cleaner CLI parsing via FromStr
• Self-documenting code (domain intent visible in function signatures)

What?

Introduce small, validated newtypes to replace raw primitives in CLI arguments and domain structures.

Each type should:

• Be a thin wrapper around a primitive
• Validate its input in a new() constructor
• Implement FromStr for easy integration with Clap (value_parser!())

Proposed types and constraints

Type	Underlying	Constraint
ClientNumber	String	Exactly 8 digits
AccountId	String	Exactly 32 hex chars
SymbolId	String	6–12 alphanumeric chars
OrderQuantity	u64	Positive, non-zero
MoneyAmount	f64	Positive, up to 2 decimals
TransferReason	String	Optional, ≤ 50 chars (letters only)
QuoteLength	enum	One of: 1, 5, 30, 90, 180, 365, 1825, 3650
QuotePeriod	i64	Non-negative period value
MfaCode	String	4–12 digits
Password	String	Non-empty

Main impact

• Stronger validation at input parsing time (fail-fast behavior)
• Reduced duplication of validation logic across commands
• Safer internal API and more expressive function signatures
• Minimal runtime overhead (just validation + wrapper)