[FaizanUllahDev]

Description

Addresses #2775.

The shared all_plugins workflow currently runs Dart analysis across the entire Plus Plugins workspace for every pull request, even when a change affects only one plugin.

This can surface unrelated analyzer findings and increases unnecessary CI work.

This PR scopes analysis to the affected plugin families while preserving full-workspace validation when needed.

Changes

• Determine changed plugin families from the pull request's Git diff against the base branch.
• Analyze only affected plugin families, including their platform interfaces and example applications.
• Deduplicate plugin families so each is analyzed once.
• Preserve full-workspace analysis for changes outside packages/, including CI and workspace configuration.
• Preserve full-workspace analysis for pushes to main.
• Retain dart analyze . --fatal-infos so analyzer warnings and errors remain actionable.
• Configure the analyzer job to fetch full Git history for accurate merge-base comparisons.
• Add automated shell regression tests for the analysis selector.

Testing

Local verification

• Shell syntax validation passed.
• Single-plugin changes select only the affected family.
• Multi-plugin changes select each affected family once.
• Workspace configuration changes trigger full analysis.
• Push events retain full analysis.
• Missing pull request base references fail safely.
• Full Flutter/Melos analysis — pending CI.
• GitHub Actions workflow verification — pending PR creation.

All five local regression scenarios passed.

Changed Files

• .github/workflows/all_plugins.yaml
• .github/workflows/scripts/analyze-changed-packages.sh
• .github/workflows/scripts/test-analyze-changed-packages.sh

Scope

This PR changes only the CI analysis workflow and associated scripts.

No plugin runtime implementations, public APIs, package versions, or changelogs are modified.

Related Issue

#2775

Checklist

• Followed the repository's contribution conventions.
• Used a Conventional Commit PR title.
• Added regression tests.
• Kept the change focused on CI.
• Left package versions and changelogs unchanged.
• Awaiting upstream CI validation and maintainer review.

Breaking Changes

None.