feat: add generate() to structural validators

[jan-kubica]

Summary

• Add generate() functions to 27 structural (no-checksum) validators
• Each generator produces random values that pass the corresponding validate() function
• Added to: AD NRT, AI TIN, AL NIPT, AM TIN, AR DNI, AT Firmenbuchnummer, BD NID, BIC, CR CPF, DE Handelsreg, DE StNr, EG TN, GB NINO, GE PIN, IN PAN, IQ NID, IS VSK, KR BRN, LI PEID, MU BRN, NG NIN, NL KvK, PH PhilID, PK CNIC, US EIN, US ITIN, US SSN

Test plan

• All existing tests pass (bun test)
• Existing "examples are all valid" tests cover generate() indirectly

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[greptile-apps]

Greptile Summary

This PR adds generate() functions to 27 structural (checksum-free) validators, creating a consistent contract where validate(generate()) always returns { valid: true }. The generators are well-structured, make good use of the shared randomInt/randomDigits helpers, and correctly implement the more nuanced validators (e.g. SSN blacklist retry loop, NINO invalid-prefix rejection, KR BRN component constraints, ITIN allowed-group filtering).

Key observations:

• All generators were verified to produce values that satisfy their corresponding validate() logic.
• The US SSN and GB NINO generators properly handle rejection/retry loops for invalid values.
• src/ai/tin.ts uses Math.random() < 0.5 for prefix selection instead of the randomInt helper used by every other generator in this PR.
• src/ad/nrt.ts silently omits valid NRT prefixes "A", "F", and "L" (which have digit-range constraints); all generated values are still structurally valid but the omission is undocumented.
• src/bic.ts hardcodes only 7 country codes while the validator accepts any [A-Z]{2} code, unnecessarily limiting generated value diversity.

Confidence Score: 4/5

• Safe to merge — all generators produce values that pass their validators; remaining issues are style/consistency concerns only.
• The core contract (validate(generate()) === valid) holds across all 27 generators after careful review. Previously raised issues (SSN blacklist guard, EIN/Handelsreg randomInt consistency) have been addressed. Remaining gaps are cosmetic: one generator uses Math.random() instead of randomInt, one silently skips valid prefixes without a comment, and the BIC generator has an unnecessarily narrow country-code pool. None of these are runtime correctness issues.
• src/ai/tin.ts (Math.random inconsistency), src/ad/nrt.ts (undocumented prefix omission), src/bic.ts (hardcoded country list)

Important Files Changed

Filename	Overview
src/ad/nrt.ts	Generator is correct but silently omits valid prefixes "A", "F", "L" which have digit-range constraints; all generated values still pass validate().
src/ai/tin.ts	Uses Math.random() < 0.5 for prefix selection instead of the randomInt helper used consistently across all other generators in this PR.
src/bic.ts	Generator hardcodes only 7 country codes despite the validator accepting any [A-Z]{2} code; limits diversity of generated test values.
src/us/ssn.ts	Generator correctly avoids area "000", "666", 900–999, group "00", serial "0000", and all three blacklisted SSNs via the outer for(;;) loop.
src/us/itin.ts	Generator correctly constrains area to start with "9" and group to 70–99 excluding 89 and 93, matching the validator exactly.
src/gb/nino.ts	Generator correctly rejects both invalid first/second letter sets and invalid two-letter prefixes via a do-while loop; format and suffix are correct.
src/kr/brn.ts	Generator correctly enforces all three validator constraints: office ≥ 101, bizType ≠ "00", serial ≠ "0000".
src/in/pan.ts	Generator correctly selects holder type from the same HOLDER_TYPES string used by the validator and produces a 10-character value matching PAN_RE.
src/pk/cnic.ts	Generator correctly produces 13 digits with province from VALID_PROVINCES (1–7) and gender digit from 1–9, satisfying all validator constraints.
src/us/ein.ts	Generator uses a comprehensive hardcoded list of valid EIN prefixes and consistently uses randomInt for selection.

Sequence Diagram

sequenceDiagram
    participant Caller
    participant generate
    participant validate

    Caller->>generate: generate()
    activate generate
    generate->>generate: randomInt / randomDigits
    generate-->>Caller: structurally valid string
    deactivate generate

    Caller->>validate: validate(generated)
    activate validate
    validate->>validate: compact()
    validate->>validate: length / format checks
    validate->>validate: component checks (RMO, prefix, group…)
    validate-->>Caller: { valid: true, compact: … }
    deactivate validate

    note over generate,validate: Contract: validate(generate()) must always return valid: true

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_{Reviews (2): Last reviewed commit: "fix: address review comments" | Re-trigger Greptile}

[jan-kubica]

All items addressed in b9d7037:

1. ITIN unused import: Fixed — replaced Math.random with randomInt for group selection.
2. SSN blacklist gap: Fixed — added BLACKLIST check in generate loop; dropped unused randomDigits import.
3. Math.random inconsistency: Fixed — handelsreg and ein now use randomInt for array selection, consistent with all other generators.

CC on behalf of @jan-kubica

[devin-ai-integration]

Devin Review found 2 new potential issues.

View 6 additional findings in Devin Review.