fix(articles): article ROT/RUT prefill was dead for every dashboard-created article (#1651)

* fix(articles): article ROT/RUT prefill was dead for every dashboard-created article

Follow-up to #1634. The user re-tested and picking a RUT article still left
the line on "Ingen": the article form has always stored the bare kind
('ROT'/'RUT'), while the prefill only recognised Skatteverket work-type codes
(BYGG, STAD, ...). On prod every dashboard-created ROT/RUT article holds the
bare kind, so the fix in #1634 never fired for a real user, and worse, since
the helper returned null for those values, picking such an article CLEARED a
deduction the user had set manually on the row.

- rot-rut-rules: parseArticleHouseworkType() understands both vocabularies
  (code -> kind + arbetstyp; bare ROT/RUT -> kind only), plus
  normalizeHouseworkType()/HOUSEWORK_TYPE_VALUES/workTypeLabel().
- InvoiceEditor.applyArticle: kind-only articles pre-fill the deduction and
  keep a same-kind arbetstyp already chosen on the row; "Spara som artikel"
  round-trips the code or, lacking one, the kind.
- ArticleForm: the ROT/RUT select now offers the real Skatteverket arbetstyper
  in ROT/RUT groups (its own hint always promised "förifyller arbetstyp");
  legacy kind-only values stay selectable as "RUT (arbetstyp ej vald)" so an
  edit never silently drops the flag. Article detail renders "RUT · Städning"
  instead of the raw code.
- API + MCP commit schemas normalize housework_type (case-insensitive code or
  ROT/RUT, '' clears) and reject anything else; the CSV article import
  normalizes the column the same way. Prod holds 178 articles with '0'/'1'
  from a boolean "Rot" column that the keyword detector mapped straight
  through; those now read as no flag everywhere and can no longer be created.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(articles): review follow-ups on #1651

- InvoiceEditor: switching a row's skattereduktion ROT<->RUT clears an
  arbetstyp from the other list, and Spara som artikel only round-trips a
  work type that belongs to the row's kind (CodeRabbit).
- MCP update_article: null / '' / whitespace now clear housework_type
  (commit drops only undefined keys, so the old undefined mapping made the
  flag un-clearable); create keeps treating them as unset. Tests.
- Article CSV import warns when a non-empty ROT/RUT value is dropped as
  not-an-arbetstyp instead of dropping it silently. Test.
- Hint wording: arbetstyp is pre-filled only when the article carries one.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

lib/api/schemas.ts

@@ -13,6 +13,7 @@ import { DimensionsBagSchema } from '@/lib/bookkeeping/dimension-resolver'
 import { validateEmployeeBankAccount } from '@/lib/salary/payment/bank-account'
 import { MAX_INVOICE_EMAIL_COPY_RECIPIENTS } from '@/lib/invoices/email-recipients'
 import { INVOICE_POSTING_ACCOUNT_REGEX } from '@/lib/invoices/posting-account'
+import { HOUSEWORK_TYPE_VALUES, normalizeHouseworkType } from '@/lib/invoices/rot-rut-rules'
 import { PERSONAL_NUMBER_INPUT_RE } from '@/lib/customers/mask-personal-number'
 import type { AuditAction } from '@/types'
 import type { BankFileFormatId } from '@/lib/import/bank-file/types'
@@ -637,6 +638,32 @@ export const RotRutBeslutFileSchema = z.object({
 
 export const ArticleTypeSchema = z.enum(['vara', 'tjanst'])
 
+/**
+ * articles.housework_type: a Skatteverket arbetstypskod (BYGG, EL, ..., STAD,
+ * TRADGARD, ...) or the bare kind ROT / RUT (deduction only, no arbetstyp
+ * pre-fill). Case-insensitive, stored upper-case; '' clears to null. The
+ * invoice editor derives a line's skattereduktion from this value, so any
+ * other string is a silently dead flag and is rejected here.
+ */
+export const HouseworkTypeSchema = z
+  .string()
+  .max(64)
+  .nullable()
+  .optional()
+  .transform((v, ctx) => {
+    if (v == null) return v
+    if (v.trim() === '') return null
+    const normalized = normalizeHouseworkType(v)
+    if (!normalized) {
+      ctx.addIssue({
+        code: z.ZodIssueCode.custom,
+        message: `Ogiltig ROT/RUT-arbetstyp. Tillåtna värden: ${HOUSEWORK_TYPE_VALUES.join(', ')}`,
+      })
+      return z.NEVER
+    }
+    return normalized
+  })
+
 export const CreateArticleSchema = z.object({
   name: z.string().min(1, 'Article name is required').max(200),
   type: ArticleTypeSchema.optional(),
@@ -655,7 +682,7 @@ export const CreateArticleSchema = z.object({
   cost_price: nonNegativeAmount.nullable().optional(),
   ean: z.string().max(32).nullable().optional(),
   // ROT/RUT arbetstyp; only meaningful for type === 'tjanst'.
-  housework_type: z.string().max(64).nullable().optional(),
+  housework_type: HouseworkTypeSchema,
   name_en: z.string().max(200).nullable().optional(),
   notes: z.string().max(2000).nullable().optional(),
   // Manual article number; omit to auto-generate via generate_article_number.