ci: bootstrap of release strategy change from rolling to versioned

[gildesmarais]

This pull request introduces automated release management and versioning for the project, including configuration for release-please, Docker image publishing, and artifact verification. It establishes a formal release process tied to CI validation, adds a canonical version constant, and ensures generated artifacts are kept up-to-date. The most important changes are grouped below:

Release Automation and Versioning:

• Added .github/workflows/release.yml to automate releases using release-please, ensuring releases only occur after successful CI on main, and Docker images are published with proper metadata and versioning.
• Introduced .github/release-please-config.json and .github/.release-please-manifest.json to configure and track release-please-managed versions, and added config/version.rb to define the canonical application version (Html2rss::Web::VERSION). [1] [2] [3]
• Added CHANGELOG.md to document notable changes in each release.

CI/CD Workflow Updates:

• Removed the Docker publish job from .github/workflows/ci.yml and replaced it with a more robust, release-gated Docker publishing process in the new release workflow. [1] [2]
• Added .github/workflows/release_artifacts.yml to verify and refresh generated OpenAPI artifacts on release branches and pull requests, ensuring generated files are always current.

Build and Metadata Improvements:

• Updated Dockerfile to accept and propagate BUILD_TAG and GIT_SHA as build arguments for improved traceability in image metadata.

Testing and Documentation:

• Added spec/html2rss/web_spec.rb to test that the canonical version constant is defined and correctly formatted.
• Updated OpenAPI spec support in spec/support/openapi.rb to use the version constant and improved code formatting. [1] [2] [3]
• Documented the release automation process in docs/README.md.

[Copilot]

Pull request overview

This PR introduces release automation via release-please, centralizes the application version into config/version.rb, and adjusts CI/release workflows to publish Docker images and keep generated OpenAPI artifacts up to date.

Changes:

• Add config/version.rb as the canonical version source and wire it into OpenAPI generation.
• Add release-please configuration + manifest and introduce release.yml / release_artifacts.yml workflows.
• Move Docker publish responsibilities out of the main CI workflow into the release workflow; add build metadata env vars to the Docker image.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
spec/support/openapi.rb	Uses the centralized app version constant for OpenAPI metadata.
spec/html2rss/web_spec.rb	Adds a spec asserting the app VERSION constant.
config/version.rb	Introduces a canonical Html2rss::Web::VERSION constant for release tooling and runtime use.
Dockerfile	Adds BUILD_TAG/GIT_SHA build args and exports them as runtime env vars.
CHANGELOG.md	Adds an initial changelog file for release-please to maintain.
.github/workflows/release_artifacts.yml	Adds an automation workflow to refresh/commit generated OpenAPI artifacts on release-please PRs.
.github/workflows/release.yml	Adds a release-please driven release workflow and Docker publish job.
.github/workflows/ci.yml	Removes the main-branch Docker publish job from CI (publish now handled in release workflow).
.github/release-please-config.json	Configures release-please to manage Ruby releases using config/version.rb and CHANGELOG.md.
.github/.release-please-manifest.json	Seeds release-please manifest with the current version.

[Copilot]

Pull request overview

This PR introduces a versioned release process (moving away from rolling releases) by adding release-please configuration, a canonical Ruby version constant, and GitHub Actions workflows to create releases, publish Docker images on release, and keep generated OpenAPI artifacts in sync with release PRs.

Changes:

• Add release automation via release-please and a release workflow that publishes Docker images only when a release is created.
• Introduce Html2rss::Web::VERSION as the canonical version source and update OpenAPI/test usage accordingly.
• Add a workflow to verify/refresh generated OpenAPI artifacts on release-please branches, plus an initial CHANGELOG.md.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
spec/support/openapi.rb	Switch OpenAPI application version from a hardcoded value to the canonical version constant.
spec/html2rss/web_spec.rb	Add a spec validating presence/format of the canonical version constant.
config/version.rb	Define Html2rss::Web::VERSION for release/version tracking.
Dockerfile	Add build metadata (BUILD_TAG, GIT_SHA) as build args and runtime env vars.
CHANGELOG.md	Introduce a changelog file for release-please managed releases.
.github/workflows/release_artifacts.yml	Add automation to verify/refresh generated OpenAPI artifacts on release-please PRs/branch.
.github/workflows/release.yml	Add release-please driven release workflow plus Docker publishing on release creation.
.github/workflows/ci.yml	Remove Docker publishing from CI so publishing happens only on releases.
.github/release-please-config.json	Configure release-please for Ruby releases, version file, and changelog path.
.github/.release-please-manifest.json	Initialize release-please manifest with the starting version.

[Copilot]

Pull request overview

This PR introduces a versioned release strategy for html2rss-web by adding release-please based automation, tying Docker image publishing to created releases, and centralizing the canonical app version in a Ruby constant.

Changes:

• Added GitHub Actions workflows for release automation (release-please) and for keeping generated OpenAPI artifacts in sync on release-please branches/PRs.
• Introduced a canonical Ruby version constant (config/version.rb) and updated OpenAPI generation/tests to consume it.
• Moved Docker publishing out of CI and into the release workflow; added build metadata wiring (BUILD_TAG, GIT_SHA) and initialized CHANGELOG.md.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
spec/support/openapi.rb	Uses canonical app version constant for OpenAPI generation and avoids top-level return in a required file.
spec/html2rss/web_spec.rb	Adds a spec to assert the canonical version constant is present and semver-shaped.
docs/README.md	Documents the new release automation and CI gating expectations.
config/version.rb	Defines canonical application version for release-please and spec/OpenAPI consumers.
Dockerfile	Adds build args/env vars for release metadata (BUILD_TAG, GIT_SHA).
CHANGELOG.md	Adds changelog file for release-please to update.
.github/workflows/release_artifacts.yml	Verifies and optionally refreshes generated OpenAPI artifacts for release-please branches.
.github/workflows/release.yml	Adds release-please release workflow and Docker image publishing on release creation.
.github/workflows/ci.yml	Removes Docker publish job so CI no longer pushes images on every main push.
.github/release-please-config.json	Configures release-please for Ruby releases using config/version.rb and CHANGELOG.md.
.github/.release-please-manifest.json	Initializes release-please manifest version tracking.