v0.2.0

Added

• LICENSE (MIT) and a README License section explaining that libpiper and the espeak-ng data
  (piper1-gpl) are GPL-3.0.
• bin/lint.sh, the single entry point for every static check: composer validate and audit,
  PHP-CS-Fixer, PHPStan, Rector and shellcheck. --fix applies the fixers first. composer lint,
  composer lint:fix and make lint call it. Closes #1.
• The shared development process: docs/workflow.md, docs/release-workflow.md, AGENTS.md,
  bin/pick-issue.sh, bin/worktree*.sh, a pull request template and Dependabot.
• release.yml creates the GitHub Release from the CHANGELOG.md section and attaches the
  libpiper archives.

Changed

• PHP-CS-Fixer (PER-CS 2.0) replaces PHP_CodeSniffer; phpcs.xml.dist is gone.
• Dev dependencies are locked: composer.lock is committed and CI runs composer install.
• CI: the lint job runs only bin/lint.sh; jobs run only for code changes; unit tests run on
  PHP 8.2 to 8.5; an aggregate ci-ok check is the one to require. CI no longer runs on tag
  pushes.
• Releases are built by release.yml instead of ci.yml. The GitHub Release notes now come from
  CHANGELOG.md; the five archives are the same as in 0.1.8.
• The PHP sources and bin/piper-tts are reformatted to PER-CS 2.0. There is no change in
  behaviour or in the public API.