fix: Attempt to run the Firebase CLI via npx if it's not installed

[samedson]

Description

When you run the flutterfire_cli via the Gemini CLI, we're running into users that don't have the Firebase CLI installed. Because the Firebase MCP server runs via npx, users don't install the Firebase CLI to their PATH.

To ensure compatibility, we're suggesting that we run the Firebase CLI via npx as a backup if it doesn't exist.

Type of Change

• ✨ feat -- New feature (non-breaking change which adds functionality)
• 🛠️ fix -- Bug fix (non-breaking change which fixes an issue)
• ❌ ! -- Breaking change (fix or feature that would cause existing functionality to change)
• 🧹 refactor -- Code refactor
• ✅ ci -- Build configuration change
• 📝 docs -- Documentation
• 🗑️ chore -- Chore

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[github-actions]

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[russellwheatley]

@samedson - Thank you for this. Could you fix the analyser issues?

https://github.com/invertase/flutterfire_cli/actions/runs/18232587025/job/51919321046?pr=415#step:5:19

Then I'll run the CI workflow 👍

[github-actions]

Hello 👋, this PR has been opened for more than 2 months with no activity on it.

If you think this is a mistake please comment and ping a maintainer to get this merged ASAP! Thanks for contributing!

You have 15 days until this gets closed automatically