Add Pretty Table project: plan, accepted documents and code

Business Case, Stakeholder Analysis, Project Plan and milestone MIL-001
with review records RC-001 to RC-003, then the Python project: PrettyTable
Pokemon table, constants, pytest tests, pyproject.toml, Doxyfile, CI
workflow and README.

Task: MIL-001#1
Task: MIL-001#2
Task: MIL-001#3
Task: MIL-001#4
Task: MIL-001#5
Task: MIL-001#6
Task: MIL-001#7
Task: MIL-001#8

docs/artifact-registry.md

@@ -0,0 +1,58 @@
+# Artifact Registry
+
+This project's artifact state. Types, short names and `CrossReference
+Candidates` come from the framework catalog
+(`framework/registry/artifact-catalog.md`); this file only records where
+each document lives in *this* project and the next version to use.
+
+Delete rows for types you don't use. Add a row the first time you create a
+document of a type. `Primary File` may contain a glob (e.g.
+`docs/uc-*/uc.md`); `framework/scripts/find-crossreferences.sh` reads it.
+
+| Short Name | Artifact Type | Primary File | Next Available Version |
+| --- | --- | --- | --- |
+| BC | Business Case | docs/business-case.md | 002 |
+| SA | Stakeholder Analysis | docs/stakeholder-analysis.md | 002 |
+| PP | Project Plan | docs/project-plan.md | 002 |
+| MIL | Milestone / Gateway | docs/milestones/*.md | 002 |
+| RC | SQA Review Record | docs/sqa/reviews/rc-*.md | 004 |
+
+## Languages
+
+Set the PO language when the project starts; `project-planning` asks for it
+if it is missing. An artifact of a type marked "Written in the PO language"
+exists once, in that language, under its normal name (`business-case.md`); the
+`artifact` skill ("One file per artifact") has the rule.
+
+| Setting | Value |
+| --- | --- |
+| PO language | en |
+| PO domain | it |
+| High-level register | IT Executive English |
+| Technical register | IT Professional English |
+
+Every artifact of a type marked "Yes" below states its language and domain in
+its `Language` and `Domain` Metadata rows; `new-artifact.sh` fills them from
+`PO language` and `PO domain`. `Language` is a BCP 47 code (`da`, `en`).
+`Domain` is a value from this list; add a row to introduce a domain, so a
+reviewer can see at once which professional vocabulary a document uses.
+
+| Domain | Meaning |
+| --- | --- |
+| it | Software and IT |
+| medical | Healthcare and medical devices |
+| construction | Construction and civil engineering |
+
+| Artifact types | Register | Written in the PO language |
+| --- | --- | --- |
+| BC, KPI, PP, MIL | IT Executive English | Yes |
+| SA, BMC, BPMN, UCD, US, UC, SSD, DM, RA, GOV, DICT | IT Professional English | Yes |
+| OC, SD, DCD, ERD, ADR, TM, RC, QC, source code | IT Professional English | No |
+
+## Notes
+
+- "Next Available Version" is the zero-padded (3-digit) version to use the
+  *next* time a new document of that type is created. Increment it only when
+  a brand-new document is created, not when an existing document's
+  `## Version History` gets a row.
+- `ADR` uses 4 digits (`0001`); `RC` is sequential across all artifact types.