Add Bic (finance)

[vhrcgcom]

Description

Implement Bic as a ValueObject in the finance module.

Spec: BIC/SWIFT, 8 or 11 chars

Implementation checklist

• Create src/finance/bic.rs
• Implement ValueObject trait
• Add #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
• Export from src/finance/mod.rs and prelude
• Unit tests: valid input · empty input · invalid format · normalisation
• Doc comment with # Example block
• Update status in ROADMAP.md from ⬜ to ✅

Implementation detail

Input / Output

	Type	Alias
Input	String	BicInput
Output	String	BicOutput

Normalization

Trim, convert to uppercase.

Validation

• Must be 8 or 11 alphanumeric characters.
• Structure: BBBB CC LL [BBB] (no spaces in the actual value):
  • Positions 1–4: bank code — 4 ASCII letters.
  • Positions 5–6: country code — 2 ASCII letters.
  • Positions 7–8: location code — 2 alphanumeric characters.
  • Positions 9–11 (optional): branch code — 3 alphanumeric characters.

Extra methods

• bank_code() -> &str — first 4 characters.
• country_code() -> &str — characters 5–6.
• location_code() -> &str — characters 7–8.
• branch_code() -> Option<&str> — characters 9–11 if present (11-char BIC), None for 8-char BIC.

References

• ROADMAP.md
• CONTRIBUTING.md