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

.agents/skills/artifact/templates/UCD.md

@@ -0,0 +1,52 @@
+# @TITLE@
+
+## Metadata
+| Key | Value |
+| --- | --- |
+| ID | @ID@ |
+| CrossReference | @CROSSREF@ |
+| Language | @LANGUAGE@ |
+| Domain | @DOMAIN@ |
+
+## Version History
+| Date | Status | Author | Reviewer | Change | Commit |
+| --- | --- | --- | --- | --- | --- |
+| @DATE@ | Proposed | @AUTHOR@ | <reviewer S-ID> | Initial version | pending |
+
+---
+
+## Purpose and Scope
+
+<system boundary in words>
+
+## Diagram
+
+```plantuml
+@startuml
+left to right direction
+actor "Name" as A1
+rectangle "System Name" {
+  usecase "Verb-phrase goal" as UC1
+}
+A1 --> UC1
+@enduml
+```
+
+## Actor Table
+
+| Actor | Stereotype | Stakeholder ID (SA) | Goals (use cases) |
+| --- | --- | --- | --- |
+
+## Use Case Table
+
+| Use Case | Actor(s) | Goal |
+| --- | --- | --- |
+
+## Relationships
+
+| From | Relationship (`<<include>>` / `<<extend>>`) | To | Justification |
+| --- | --- | --- | --- |
+
+---
+
+@LINKS@