feat(invoicing): artikelregister (product/article catalog) with per-article revenue account (#703)

* feat(invoicing): artikelregister (product/article catalog) with per-article revenue account

Add a lean, non-inventory article catalog (artikelregister) so users can define
reusable invoice-line presets (name, unit, price excl VAT, VAT rate) with an
optional per-article BAS class-3 revenue-account override.

- DB: articles table (RLS via user_company_ids(), audit + updated_at triggers,
  unique-per-company article_number), generate_article_number RPC (atomic +
  idempotent), company_settings counter, nullable invoice_items.revenue_account
  + article_id, pending_operations CHECK expansion.
- Engine: generatePerRateLines groups revenue by (vat_rate, account) —
  byte-identical with no override, balance-safe when split (last account absorbs
  the rounding remainder), reverse_charge/export still force 3308/3305.
- API: /api/articles CRUD (soft-deactivate); override validated against
  chart_of_accounts (active class-3) and frozen onto invoice lines at create.
- Propagation: override carried through send/mark-sent/credit/convert/cash and
  the staged commit paths (recurring deferred — documented inline).
- MCP: gnubok_list/create/update_article (staged, scoped, risk-tiered).
- UI: articles register (list/detail/form) + nav + bilingual i18n + invoice-line
  article picker & "Spara som artikel" quick-create.
- Tests: engine regression, route, and pg-real (RPC/RLS/triggers).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(mcp): strip ILIKE _ wildcard from gnubok_list_articles search

Underscore is a single-character ILIKE wildcard; stripping it (alongside the
existing %,()\* set) keeps a stray char in the article search from matching
every row. Read-only + RLS-scoped, so no security impact — addresses PR #703
reviewer + compliance-swarm CC6.3 notes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

types/index.ts

@@ -580,6 +580,57 @@ export interface Supplier {
   updated_at: string
 }
 
+// Article (artikelregister) — reusable invoice-line preset. NON-INVENTORY:
+// no stock fields and no inventory postings, by deliberate design.
+export type ArticleType = 'vara' | 'tjanst'
+
+export interface Article {
+  id: string
+  company_id: string
+  user_id: string
+
+  /** Auto-numbered per company (generate_article_number RPC); user-overridable. */
+  article_number: string | null
+  name: string
+  /** English benämning for English-language invoices. */
+  name_en: string | null
+  type: ArticleType
+  unit: string
+  /** Always stored EXCLUDING VAT. */
+  price_excl_vat: number
+  /** Default line VAT rate as an integer percent: 25 | 12 | 6 | 0. */
+  vat_rate: number
+  /** Optional BAS class-3 revenue account override. null = derive from VAT treatment. */
+  revenue_account: string | null
+  /** Margin/display only — never posted to the ledger. */
+  cost_price: number | null
+  ean: string | null
+  /** ROT/RUT arbetstypskod (tjänst only); pre-fills the invoice line. */
+  housework_type: string | null
+  notes: string | null
+  /** Soft-delete flag. Inactive articles are hidden from pickers but keep history. */
+  active: boolean
+
+  created_at: string
+  updated_at: string
+}
+
+export interface CreateArticleInput {
+  name: string
+  type?: ArticleType
+  unit?: string
+  price_excl_vat: number
+  vat_rate?: number
+  revenue_account?: string | null
+  cost_price?: number | null
+  ean?: string | null
+  housework_type?: string | null
+  name_en?: string | null
+  notes?: string | null
+  /** Optional manual article number; omit to auto-generate. */
+  article_number?: string | null
+}
+
 // Supplier Invoice
 export interface SupplierInvoice {
   id: string
@@ -826,6 +877,14 @@ export interface InvoiceItem {
   vat_rate: number
   vat_amount: number
 
+  // Article linkage. `article_id` is a soft back-reference to the source
+  // article (for the "Affärshändelser" history view); `revenue_account` is the
+  // BAS class-3 account frozen-copied from the article at line-create time.
+  // null `revenue_account` preserves the legacy "derive from VAT treatment"
+  // booking in generatePerRateLines().
+  article_id?: string | null
+  revenue_account?: string | null
+
   // ROT/RUT-avdrag (Sweden's tax deduction for household services / home
   // renovation). When `deduction_type` is set, the system computes
   // `deduction_amount` from the rules in lib/invoices/rot-rut-rules.ts
@@ -1019,6 +1078,10 @@ export interface CreateInvoiceItemInput {
   unit: string
   unit_price: number
   vat_rate?: number
+  /** Source article (optional). Free-text lines omit it. */
+  article_id?: string | null
+  /** BAS class-3 revenue account override copied from the article. null = derive from VAT treatment. */
+  revenue_account?: string | null
   /** ROT/RUT toggle. null/undefined = no deduction. */
   deduction_type?: 'rot' | 'rut' | null
   labor_hours?: number | null
@@ -1552,6 +1615,8 @@ export interface CreateFiscalPeriodInput {
 export type PendingOperationType =
   | 'categorize_transaction'
   | 'create_customer'
+  | 'create_article'
+  | 'update_article'
   | 'create_supplier'
   | 'create_invoice'
   | 'mark_invoice_paid'