Add inception baseline and milestone plan for Higher Lower

Add the Business Case, Stakeholder Analysis and Project Plan, and four
milestones (MIL-001 Project setup, MIL-002 Game logic, MIL-003 Console
game, MIL-004 Documentation and release) with Go/No-Go criteria and
task tables.

Set the PO language to en in the artifact registry. Link the synced
Gitea Milestones (36-39) in the Project Plan. The 20 task rows were
synced as issues #1-#20.

Refs #5

docs/business-case.md

@@ -0,0 +1,124 @@
+# Business Case
+
+## Metadata
+| Key | Value |
+| --- | --- |
+| ID | BC-001 |
+| CrossReference | [SA-001], [PP-001] |
+
+## Version History
+| Date | Status | Author | Reviewer | Change | Commit |
+| --- | --- | --- | --- | --- | --- |
+| 2026-10-04 | Proposed | Jens Tirsvad Nielsen | S01 | Initial version | pending |
+
+---
+
+## Executive Summary
+
+Build the "Higher Lower" console game from Udemy's 100 Days of Code (day 14) as a small, readable, dependency-free Python project. The player compares two Instagram accounts and guesses which has more followers; a correct guess adds a point and continues, a wrong guess ends the game. The repository is a learning artefact that other course participants and GitHub visitors can read, run and compare against.
+
+## Methodological and Standards Foundation
+
+Planning follows the project's SQA/QC framework (`framework/`): Business Case, Stakeholder Analysis, Project Plan, milestones synced as Gitea Milestones and Issues, then code. Product quality is described with ISO/IEC 25010:2023 characteristics.
+
+## Problem Statement
+
+The course assignment gives only a brief and a data set. Without a structured, tested and documented solution there is nothing to share, compare or reuse, and the practice value of the exercise is lost.
+
+## Business Opportunity
+
+A clean reference solution with the assignment's function names, tests and run instructions lets fellow participants compare approaches, and shows the author's practice of planning-first, tested development.
+
+## Objectives
+
+1. O1 — Deliver a playable console Higher Lower game using the assignment's data set, art and function names.
+2. O2 — Keep the code readable: constants in `constants.py`, Doxygen comments in source, Python 3.13+.
+3. O3 — Provide pytest tests for the game logic and the game loop.
+4. O4 — Provide a README with venv, pip upgrade, run and test instructions, and a Doxyfile.
+5. O5 — Publish the repository with a clear description and topics.
+
+## Scope
+
+### In Scope
+
+- Console game: random pair selection, score tracking, one session that ends on a wrong guess.
+- Assignment data set (50 entries), `logo` and `vs` ASCII art.
+- `src/`, `tests/`, `docs/` layout, `pyproject.toml`, Python `.gitignore`, `Doxyfile`, `README.md`.
+- Repository description and topics on the Gitea repository.
+
+### Out of Scope
+
+- Graphical or web user interface.
+- Live data from Instagram or Google Trends.
+- Persistent high scores.
+- Runtime third-party dependencies.
+- Committing or pushing (done by the author after review).
+
+## Expected Benefits
+
+### Tangible Benefits
+
+- A runnable, tested repository other participants can clone.
+- A reusable planning and documentation trail.
+
+### Intangible Benefits
+
+- Practice in decomposing a problem into small tasks and testing incrementally.
+- Visibility of the author's work to GitHub viewers.
+
+## Strategic Alignment
+
+Supports the author's goal of completing the 100 Days of Code bootcamp with professional-quality practice (planning, tests, documentation).
+
+## Success Criteria
+
+| # | Criterion | Target | Measure |
+| --- | --- | --- | --- |
+| 1 | Game is playable | A full game runs from `python -m higher_lower` | Manual run |
+| 2 | Tests pass | All pytest tests pass | `pytest` exit code 0 |
+| 3 | No runtime dependencies | `dependencies = []` in `pyproject.toml` | File inspection |
+| 4 | Docs complete | README, Doxyfile and Doxygen comments present | Review record |
+| 5 | Repository metadata set | Description and topics visible on the host | Host page |
+
+## Risks
+
+| Risk | Impact | Mitigation |
+| --- | --- | --- |
+| Token from `.env` leaks into the project | Credential exposure | Keep `.env` gitignored; never import or test it; use only for host sync |
+| Data set has entries out of order (e.g. Cardi B, David Beckham) | None for gameplay; may confuse readers | Keep data verbatim; the game compares counts, not list order |
+| Same account drawn twice in a round | Meaningless round | Pair selection forces two distinct entries; tested |
+
+## Assumptions
+
+- The README template referenced in the brief will be supplied before the README task starts (see Project Plan open issues).
+- Python 3.13 or newer is installed on the author's machine.
+
+## Constraints
+
+- Python 3.13+, `venv`, pytest, `pyproject.toml`, `constants.py`.
+- No runtime dependencies unless needed.
+- Do not commit, push or open a PR without the author's request.
+- Product Owner language: English.
+
+## Cost–Benefit Assessment
+
+| Costs | Benefits |
+| --- | --- |
+| About one to two evenings of the author's time | A shareable, tested, documented reference solution |
+
+## Stakeholders
+
+| Stakeholder ID (SA) | Interest in this project |
+| --- | --- |
+| S01 | Product Owner, developer and reviewer; wants a correct, well-practised solution |
+| S02 | Udemy coursists; want readable, runnable code with the assignment's function names |
+| S03 | GitHub viewers; want a clear description, topics and README, and no dependencies |
+
+## Recommendation
+
+Proceed — the scope is small, the risks are low and the result serves all three stakeholders.
+
+---
+
+[SA-001]: ./stakeholder-analysis.md
+[PP-001]: ./project-plan.md