Add QC-LANG-001 (language and domain) and rewrite QC-DICT-001 criterion 7

QC-LANG-001 is a cross-cutting checklist for every artifact type written in the
Product Owner's language: Language and Domain metadata, content in the stated
language and register, domain terms from the dictionary, structural vocabulary
in English, no translated twin, a language change reviewed again, and domain
terms confirmed by a competent reviewer. Ten criteria, each tagged with an
ISO/IEC 25010:2023 characteristic.

QC-DICT-001 criterion 7 no longer checks translated artifacts (there are none
under the single-file rule); it checks that the dictionary's language and domain
match the project registry. Both checklists are Proposed.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

qc-language-domain.md

@@ -0,0 +1,53 @@
+# Quality Criteria: Language and Domain
+
+## Metadata
+| Key | Value |
+| --- | --- |
+| ID | QC-LANG-001 |
+| CrossReference | [QC-DICT-001] |
+
+## Version History
+| Date | Status | Author | Reviewer | Change | Commit |
+| --- | --- | --- | --- | --- | --- |
+| 2026-10-03 | Proposed | Jens Tirsvad Nielsen | S07 | Initial version | — |
+
+---
+
+## Purpose
+
+Every artifact of a type written in the Product Owner's (PO's) language exists once, in that language and in the vocabulary of its professional domain (for example medical or construction engineering, even when the language is English). This checklist decides whether such an artifact can be read and reviewed by the people it is for. It is cross-cutting: apply it in addition to the checklist of the artifact's own type, to every artifact type the project registry marks as written in the PO language.
+
+## Quality Criteria Checklist
+
+Level: **Mandatory** criteria are the baseline every instance must meet; **Optional** criteria are advanced and may be deferred.
+
+| # | Criterion | Level | ISO/IEC 25010 Characteristic(s) | Notes |
+| --- | --- | --- | --- | --- |
+| 1 | The Metadata table has a `Language` row and a `Domain` row, and neither is a placeholder | Mandatory | Usability, Maintainability | A reviewer must see at once how to read the document |
+| 2 | `Language` is a BCP 47 code and `Domain` is a value from the registry's domain list | Mandatory | Maintainability | Free-text values cannot be listed or compared |
+| 3 | The content (prose and table cells) is written in the stated language | Mandatory | Usability | Quoted source text and established technical terms may stay in another language; a document half in one language and half in another fails |
+| 4 | The register matches the one the registry gives for the artifact type | Mandatory | Usability | The register fixes the reader the text assumes and how much it explains |
+| 5 | Domain terms are the PO terms of the domain's dictionary, with no synonyms | Mandatory | Usability, Maintainability | A second word for a dictionary term is a defect |
+| 6 | Metadata keys, section headings, IDs and statuses are in English | Mandatory | Maintainability, Compatibility | The scripts read them; only the content is in the PO language |
+| 7 | No translated twin (`<name>.<language>.md`) exists beside the document | Mandatory | Maintainability | One file per artifact; two files drift apart |
+| 8 | A change of language or domain since the previous accepted version has a Version History row and was reviewed again | Mandatory | Maintainability | Changing the language of an artifact is a material change |
+| 9 | A reviewer competent in the domain, and in the language, has confirmed that the domain terms are used correctly | Mandatory | Functional Suitability | May be a second reviewer named on the review record when the first does not read the language or know the domain |
+| 10 | Abbreviations are spelled out on first use, in the stated language | Optional | Usability | |
+
+## Common Defects
+
+- A `Domain` or `Language` row left as a placeholder, or a free-text domain
+- Sections in two languages, or headings translated so that a script cannot find them
+- A PO term in the domain's dictionary replaced by a near-synonym in one section
+- The English document replaced by a translation without a Version History row or a new review
+- A translated copy kept beside the document "for convenience"
+- Domain terms used loosely because the reviewer does not know the domain
+
+## Traceability Rule
+
+- Backward: Every PO term traces to a row of the Domain Dictionary ([QC-DICT-001]) of the same domain
+- Forward: Applies together with the checklist of the artifact's own type; it feeds no other checklist
+
+---
+
+[QC-DICT-001]: ./qc-dictionary.md