feat: scaffold Symfony 8 with ITK Dev Docker setup

[martinyde]

Summary

• Scaffolds the project with the symfony-8 ITK Dev Docker template (phpfpm 8.4, nginx, MariaDB, Mailpit, Traefik routing).
• Adds a fresh Symfony 8 skeleton (symfony/skeleton:^8.0) with PSR-4 App\ autoload at src/.
• Installs dev tooling required by the CI workflows: ergebnis/composer-normalize, friendsofphp/php-cs-fixer, vincentlanglet/twig-cs-fixer.
• Replaces the placeholder README.md with local-development instructions and adds an initial CHANGELOG.md.
• Adds name/description to composer.json so composer validate --strict passes, and gitignores .twig-cs-fixer.cache.

Changes

• Symfony skeleton at bin/, config/, public/, src/, composer.json, composer.lock, symfony.lock, .env, .env.dev, .editorconfig, .gitignore.
• ITK Dev Docker template at docker-compose.yml, docker-compose.dev.yml, docker-compose.redirect.yml, docker-compose.server.yml, .docker/nginx.conf, .docker/templates/default.conf.template, .github/workflows/*, .markdownlint.jsonc, .markdownlintignore, .php-cs-fixer.dist.php, .twig-cs-fixer.dist.php, .prettierrc.yaml.
• New: README.md (replaced), CHANGELOG.md.

Testing

Local CI suite (matches the workflows under .github/workflows/):

• itkdev-docker-compose composer validate --strict — OK
• itkdev-docker-compose composer normalize --dry-run — already normalized
• itkdev-docker-compose composer audit — no advisories
• itkdev-docker-compose vendor/bin/php-cs-fixer fix --dry-run --diff — 0 of 5 files need fixing
• itkdev-docker-compose vendor/bin/twig-cs-fixer lint — 0 errors (no templates yet)
• docker compose --profile dev run --rm prettier '**/*.{yml,yaml}' --check — all match
• docker compose --profile dev run --rm markdownlint markdownlint '**/*.md' — clean

Manual smoke test: https://ai-lib.local.itkdev.dk/ returns Symfony output (404 from the Symfony router — expected for an empty route map; not a Traefik/nginx error).

Fixes #1
Closes #7

[martinydeAI]

Task-type issue coverage

Reviewed against open issues with type=Task in this repo. PR #4 covers:

• Set up Docker + Symfony #1 — Set up Docker + Symfony — already linked above via Fixes #1.
• Add CHANGELOG.md (Keep a Changelog) #7 — Add CHANGELOG.md (Keep a Changelog) — fully covered. CHANGELOG.md exists with the Keep a Changelog header and an [Unreleased] section. Suggest adding Closes #7 to the PR description so it auto-closes on merge.

Partially covered (leaving open):

• Write project README #8 — Write project README — stack and local-dev setup are documented; the project purpose (shared catalog of AI assistants for the Danish public sector) and links to the estimation/related docs are still missing.
• Set up GitHub Actions for coding standards and tests #10 — Set up GitHub Actions for coding standards and tests — CI runs the coding-standards checks (php.yaml, twig.yaml, markdown.yaml, styles.yaml, yaml.yaml, javascript.yaml, composer.yaml, changelog.yaml). A test-suite workflow (e.g. PHPUnit) is not part of this PR.

Not covered by this PR (no action needed here): #5 (CLAUDE.md), #6 (.claude/settings.json), #9 (CONTRIBUTING), #11 (ADR structure), #29 (Taskfile).

[tuj]

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