docs: normalize README structure #296

Goal

Normalize the README to the agreed 13-section structure, reducing maintenance overhead and aligning with the other five repos in the series.

Reference spec: backlog/readme-normalization.md in the nanotaboada working directory.

Final Section Order

1. Title + Badges
2. One-liner
3. Features
4. Tech Stack
5. Architecture
6. API Reference
7. Prerequisites
8. Quick Start
9. Containers
10. Environment Variables
11. Contributing
12. Command Summary
13. Legal

Remove Entirely

• Table of Contents
• Project Structure section
• Testing section (content moves — see below)
• Releases section (content moves — see below)

Modify

Features

• Cap at 6 bullets (currently has 10) — keep the most developer-facing ones (emoji + bold label + short description)

Architecture

• Remove all prose subsections (Arrow Semantics, Composition Root, Color Coding, Layered Architecture — ~300 words)
• Replace with 2–3 line callout: "Arrows follow the injection direction (A → B means A depends on B). Solid = runtime dependency, dotted = structural. Blue = core domain, red = third-party, green = tests."

API Reference

• Add HTTP response codes table (model it on the one in rust-samples-rocket-restful)
• Confirm Swagger UI link is present (springdoc-openapi-starter-webmvc-ui)
• Add .rest file mention if file exists in the repo

Prerequisites

• Keep macOS-specific JAVA_HOME note as a callout

Containers

• Keep note about dual ports (9000 API + 9001 actuator)
• Add Docker pull block (three tag formats: :semver, :codename, :latest) absorbed from the Releases section

Environment Variables

• Remove full application.properties file dumps — key variables + defaults only

Contributing

• Absorb testing instructions from the removed Testing section (run command, coverage command, framework name only)
• Remove BDD naming convention explanation (givenX_whenY_thenZ) — move to copilot-instructions.md instead

Command Summary

• Add AI Commands subsection at the bottom of the table:

  Command	Description
  /pre-commit	Runs linting, tests, and quality checks before committing
  /pre-release	Runs pre-release validation workflow

New File: RELEASES.md

• Create RELEASES.md with:
  • Header: naming convention — v{SEMVER}-{CLUB} (e.g., v1.0.0-arsenal), historic football clubs theme description, link to codename list in CHANGELOG.md
  • Workflow: full release steps (branch → update CHANGELOG → push → PR → tag → CD)
  • Pre-release checklist
  • Docker pull examples (three tag formats)