Extract shared Fast Forward workflows into .github

[coisa]

Objective

Move the shared Fast Forward GitHub Actions implementation from php-fast-forward/dev-tools into this organization-level .github repository, following the migration direction tracked in php-fast-forward/dev-tools#240.

Current Limitation

Consumer repositories receive thin workflow wrappers from dev-tools, but those wrappers currently call reusable workflows and composite actions hosted in php-fast-forward/dev-tools. That keeps organization automation coupled to the PHP CLI package repository and assumes consumers can run composer dev-tools from their own dependency graph.

That assumption is becoming weaker for extracted packages such as fast-forward/agents, which should be able to consume shared Fast Forward workflows without requiring fast-forward/dev-tools as a project dependency.

Proposed Work

Add the reusable workflow and composite action implementation to this repository, then introduce a dedicated setup action that guarantees the dev-tools CLI is available before shared workflows call it.

The setup action should prefer an already installed project-local dev-tools command when available, and otherwise install fast-forward/dev-tools globally through Composer with an explicit version/ref input. This lets existing repositories keep working while newly extracted repositories can use shared workflows without depending on dev-tools directly.

Scope

• Add reusable workflow files currently consumed by Fast Forward repository wrappers.
• Add composite actions required by those workflows.
• Add a dedicated action for installing or locating fast-forward/dev-tools globally.
• Update copied workflow/action paths so reusable workflows resolve local actions from this repository instead of php-fast-forward/dev-tools.
• Document the initial ownership split between .github, dev-tools, and consumer repositories.
• Keep this issue focused on the .github repository side of the migration; wrapper changes in dev-tools may be handled by a coordinated follow-up PR there.

Non-goals

• Do not remove workflow wrappers from dev-tools in this repository.
• Do not redesign the dev-tools PHP command architecture.
• Do not decide the final release-safe ref policy from Define release-safe refs for consumer workflow wrappers and checked-out actions dev-tools#238 beyond exposing a version/ref input that keeps the migration testable.
• Do not require consumer repositories to add fast-forward/dev-tools to composer.json solely to run shared workflows.

Acceptance Criteria

Delivery Criteria

• .github/workflows/ contains the shared reusable workflow implementations needed by Fast Forward consumer wrappers.
• .github/actions/ contains the composite actions required by those workflows.
• A dedicated action installs or locates fast-forward/dev-tools and exposes a command path that workflows can use consistently.
• Workflows that call composer dev-tools or related commands use the setup action first.
• The setup action supports a configurable dev-tools version/ref for branch-based testing.
• README documentation explains that .github owns shared automation while dev-tools owns PHP CLI commands and consumer wrapper synchronization.
• The implementation notes how it coordinates with Extract shared GitHub Actions automation into php-fast-forward/.github dev-tools#240 and leaves release-safe refs from Define release-safe refs for consumer workflow wrappers and checked-out actions dev-tools#238 for the next policy step.

Regression Criteria

• Static validation confirms migrated reusable workflows no longer checkout php-fast-forward/dev-tools only to access .github/actions.
• Static validation confirms migrated reusable workflows do not reference php-fast-forward/dev-tools/.github/workflows/*@main.
• YAML files and shell scripts parse successfully.
• At least one smoke check verifies the dev-tools setup action can resolve an existing local command or prepare a global Composer installation path without requiring a consumer project dependency.

Architectural / Isolation Criteria

• The change keeps automation ownership separate from dev-tools PHP package ownership.
• The setup action is reusable by multiple workflows instead of duplicating global install logic in each workflow.
• The migration avoids destructive changes to organization profile content already stored in this repository.