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/references/TRN.md

@@ -0,0 +1,18 @@
+# Reviewer Training (TRN)
+
+The reusable training material for reviewers. It mitigates the "resistance to
+standardized reviews" risk of the Business Case. Framework-level, like `PRC`:
+no project data, no stakeholder IDs, no links to project artifacts. The
+*record* that a session happened (date, attendees, result) is a project
+document, written after the session.
+
+- **File:** `framework/process/reviewer-training.md` (singleton, version `001`).
+- **Create:** `new-artifact.sh TRN`.
+- **CrossReference:** `PRC` (the procedure the training teaches).
+
+## Required sections (after Metadata / Version History)
+
+Purpose, Audience and Prerequisites, Learning Objectives, Agenda (modules with
+minutes), Module Notes, Exercises (each with input and expected result),
+Assessment (how and pass criteria), Session Record (what to capture).
+Exercises use a seeded, generic example, not a real project artifact.