Update invoice and credit note schemas to follow PEPPOL BIS Invoice 3 specification

[Copilot]

• Analyze current schemas vs OpenPEPPOL specification
• Run existing tests to establish baseline (170/170 pass, 1 pre-existing failure)
• Fix InvoicePeriodSchema - make descriptionCode optional (spec: 0..1)
• Create Delivery schema (spec: cac:Delivery 0..1)
• Create AllowanceCharge schema (document-level 0..n and line-level 0..n)
• Create AdditionalDocumentReference schema (spec: 0..n)
• Update Invoice schema - add missing fields (orderReference, billingReference, document references, delivery, allowanceCharge, projectReference)
• Update CreditNote schema - inherit new fields from Invoice, omit projectReference per credit note spec
• Update Line schema - add commodityClassification, line allowanceCharge, price baseQuantity, price allowanceCharge, update standardItemIdentification and additionalItemProperties
• Update PaymentMeans schema - add paymentDueDate for credit notes
• Update DocumentBuilder to handle new fields
• Update DocumentParser to handle new fields
• Update data files (basic-invoice.ts, basic-creditNote.ts) for schema changes
• Update common/index.ts exports
• Run tests - all 170 pass (1 pre-existing CJS build failure)
• Self-review: fix __bool helper wiring, fix this-binding bug in builder line methods

[codacy-production]

Not up to standards ⛔

🔴 Issues 11 high

Alerts:
⚠ 11 issues (≤ 0 issues of at least minor severity)

Results:
11 new issues

Category	Results
ErrorProne	11 high

View in Codacy

🟢 Metrics 8 complexity . -6 duplication

Metric	Results
Complexity	8
Duplication	-6

View in Codacy

_{TIP This summary will be updated as you push new changes. Give us feedback}

[SimonLoir]

@copilot review

[Copilot]

@copilot review

Self-review found and fixed two bugs in 093527b:

1. this-binding bug in builder — __buildInvoiceLine and _buildCreditNoteLine were passed as bare .map() callbacks (losing this) and internally called DocumentBuilder.prototype.__buildLineItem(...) (also wrong this). This would crash at runtime when a line has allowanceCharge set, since __buildLineItem calls this.__buildLineAllowanceCharge(). Fixed by calling this.__buildLineItem(line, tag) directly via arrow functions.

2. __bool helper unused — The helper was added but the two inline boolean expressions were never updated. Now wired in both __parseAllowanceCharges and __parseLineItem.