feat(ci): add force_multiplatform input to build workflow

[bedatty]

Description

Add force_multiplatform boolean input to the build workflow, allowing consumers to opt-in to multi-platform builds (amd64+arm64) for
beta/rc tags. By default, beta/rc tags continue building only amd64.

Type of Change

• feat: New feature or workflow

Affected Workflows

• GitOps Update
• API Dog E2E Tests
• PR Security Scan
• Release Workflow
• Other (specify): Build and Push Docker Images

Changes Made

• Added force_multiplatform boolean input (default: false) to the build workflow
• Updated platform selection logic to support amd64+arm64 on beta/rc tags when force_multiplatform: true
• No change to release tag behavior — always builds multi-platform

Breaking Changes

None — default value is false, preserving existing behavior.

Testing

• Tested locally
• Tested in development environment
• Tested with example repository: _______________
• All existing workflows still work

Checklist

• Code follows conventional commit format
• Documentation updated (if applicable)
• Examples updated (if applicable)
• No hardcoded secrets or sensitive data
• Backward compatible (or breaking changes documented)
• Self-review completed
• Comments added for complex logic

Related Issues

Additional Notes

Usage in consumer repos:

uses: LerianStudio/github-actions-shared-workflows/.github/workflows/build.yml@verions-released
with:
  force_multiplatform: true

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->

## Summary by CodeRabbit

* **New Features**
* Added `force_multiplatform` workflow input option to enable multi-platform builds (amd64+arm64) for beta and RC release tags.
* Beta and RC releases now support ARM64 builds when the force_multiplatform option is enabled; release tags continue multi-arch by default.

* **Documentation**
* Updated build workflow documentation with detailed platform build strategy and guidance on using the new multi-platform option.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yml

Review profile: ASSERTIVE

Plan: Pro

Run ID: 19e3f8f6-70da-41bb-901e-c39cd149eb63

📥 Commits

Reviewing files that changed from the base of the PR and between fe57eec and 949405d.

📒 Files selected for processing (2)

• .github/workflows/build.yml
• docs/build-workflow.md

---

Walkthrough

Adds a boolean workflow input force_multiplatform to the build workflow and updates platform selection: beta/RC tags build amd64 only by default but will include arm64 when force_multiplatform: true; release tags remain multi-arch. QEMU setup now follows the computed platforms (arm64 presence).

Changes

Cohort / File(s)	Summary
Build workflow \.github/workflows/build.yml	Adds force_multiplatform workflow input; adjusts beta/rc platform decision to respect this input; changes QEMU setup conditional to run when computed platforms include arm64; updates logging/messages.
Documentation docs/build-workflow.md	Documents the new force_multiplatform input and updates platform strategy table and ARM64 guidance to reflect beta/rc default amd64-only behavior and the option to force multi-arch.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Sequence Diagram(s)

mermaid
sequenceDiagram
participant GitHub as GitHub (push/tag)
participant Workflow as build.yml
participant Matrix as Platform Matrix Generator
participant QEMU as QEMU Setup
participant Runner as Build Runner (buildx)
participant Registry as Image Registry

GitHub->>Workflow: trigger (tag/push)
Workflow->>Workflow: read inputs (force_multiplatform) and tag type
Workflow->>Matrix: determine platforms (amd64 or amd64+arm64)
Matrix-->>Workflow: platforms list
alt arm64 included
Workflow->>QEMU: prepare QEMU/emulation
QEMU-->>Workflow: QEMU ready
end
Workflow->>Runner: run build jobs for platforms
Runner->>Registry: push multi-arch manifest and images
Registry-->>Runner: push complete

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately and concisely describes the main change: adding a force_multiplatform input to the build workflow.
Description check	✅ Passed	The description covers required sections: clear summary, Type of Change marked, affected workflows specified, changes documented, no breaking changes, testing notes provided, and checklists completed.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch feat/add-force-multiplatform-input

📝 Coding Plan for PR comments

• Generate coding plan

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In @.github/workflows/build.yml:
- Around line 167-175: The QEMU setup currently gated on is_release == 'true'
misses the case where inputs.force_multiplatform=true sets
platforms="linux/amd64,linux/arm64", causing arm64 jobs to run without
emulation; update the conditional that determines whether to run the QEMU setup
(the check near the QEMU setup block referenced by is_release and platforms) to
instead detect whether the platforms output contains "linux/arm64" (or otherwise
indicates an arm64 target) and run QEMU when arm64 is present; keep existing
behavior for pure amd64 builds.

---

ℹ️ Review info

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between a96ac6b and 3815633.

📒 Files selected for processing (2)

• .github/workflows/build.yml
• docs/build-workflow.md