fix(isVAT): align eight EU matchers with the official number structures

[rodrigobnogueira]

Aligns eight EU matchers with the number structures the national tax authorities and the Commission's VIES table publish, and fixes Ireland, which currently rejects every number issued to a company since 2013.

Each change still accepts every form the sources describe and rejects only shapes no authority issues. The new test vectors are real registered entities, each confirmed against VIES; the placeholder vectors that had to go were structurally impossible numbers (CY123456789 ends in a digit, LT12345678901 is a length Lithuania never issues, SE…12 has a suffix Skatteverket rules out).

Code	Before	After	Why
BE	\d{10}	[01]\d{9}	Enterprise numbers start with 0 or 1 (the 1-series opened in Sept 2023); 2–8 begin establishment-unit numbers, which are never VAT numbers.
CY	\w{9}	\d{8}[A-Z]	Eight digits and a letter. \w also admitted _ and letters in the digit positions.
IE	\d{7}\w(W)?	\d{7}[A-W][A-Z]? or \d[A-Z+*]\d{5}[A-W]	Bug fix. Numbers issued since 2013 carry a second letter other than W (IE3206488LH, Stripe) and the legacy 1X23456L form is still live in VIES (IE8F52100V, ESB); both are rejected today. The check letter is modulus 23, so only A–W.
LT	\d{9,12}	(\d{7}|\d{10})1\d	Only 9- and 12-digit codes exist, and the digit before the check digit is always 1.
NL	\d{9}B\d{2}	\d{9}B(0[1-9]|[1-9]\d)	The sub-number runs B01–B99; B00 is never issued.
RO	\d{2,10}	[1-9]\d{1,9}	No leading zero: RO19 is valid, RO019 is not.
SE	\d{12}	\d{10}01	Skatteverket: "the last two digits are always 01".
SI	\d{8}	[1-9]\d{7}	Base numbers start at 1 000 000, so the first digit is never 0.

FR was checked and left as is: the official structure defines both key characters as "a letter or a digit".

References:

• VIES, VAT identification number structure (all countries)
• BE: FPS Economy, registration in the Crossroads Bank for Enterprises
• CY: OECD, Cyprus TIN sheet · Cyprus Tax Department, new TIN format from 27 March 2023
• IE: Revenue, VIES Traders Manual §4.8 · Revenue eBrief 03/13
• LT: VMI order Nr. 178, point 21
• NL: Belastingdienst, OB4091 explanatory notes
• RO: OJ C 481/08, TIN structures
• SE: Skatteverket, momsregistreringsnummer · Skatteverket, Bilaga 9
• SI: FURS, entry into the tax register and tax number

Validation: npm test — 323 passing.

Checklist

• PR contains only changes related; no stray files, etc.
• README updated (not applicable: no country codes added or removed)
• Tests written
• References provided in PR

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (a79ff98) to head (430f931).

Additional details and impacted files

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  Coverage   100.00%   100.00%           
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  Files          114       114           
  Lines         2599      2599           
  Branches       658       658           
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  Hits          2599      2599           

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