v0.6.0 — Security audit fixes + InvoiceNumber VO Breaking changes: - InvoiceNumberingService::generateNumber() now returns InvoiceNumber VO instead of string (backward compatible via __toString()) New: - InvoiceNumber readonly value object (formatted, prefix, fiscalYear, seriesNumber) - Deprecation notice for BillingService numbering methods (removal: v0.7.0) Fixes: - Install command: respect config priority, prevent migration duplicates - Migration: use MigrationHelper for billable_user_id - Replace deprecated getValidForUserAt with getValidForOwnerAt Other: - ADR-004: rename user_id to owner_user_id in user_tax_profiles - LegalEntityTypesSeeder: add is_company field - CONTRIBUTING.md with migration pattern standards - Remove Filament dependency, make package agnostic - PHP Insights config and code quality fixes