Add AIO_DEV env flag to detect running local

[purplecabbage]

Description

Inject env var to detect if we were run by aio app dev
this can be read as truthy, it will not exist in Runtime (ie. aio app run )

console.log('AIO_DEV ', process.env.AIO_DEV ? 'dev' : 'prod')

Related Issue

adobe/aio-cli#753

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[Copilot]

Pull Request Overview

This PR introduces an environment variable flag to detect when the application is running in a local development (dev) mode as opposed to in production.

• Adds the AIO_DEV environment variable in run-dev.js to indicate a development environment.
• Includes comments to clarify that this flag is only set during local development runs.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (3b5bf4d) to head (c1e1699).
Report is 1 commits behind head on main.

Additional details and impacted files

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  Coverage   100.00%   100.00%           
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  Files            7         7           
  Lines          641       642    +1     
  Branches       132       132           
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+ Hits           641       642    +1     

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[Copilot]

Pull Request Overview

This pull request adds an environment flag (AIO_DEV) to detect when the application is running in development mode via "aio app dev".

• Introduces new environment variable AIO_DEV with a truthy value
• Adds inline comments explaining the purpose of the flag

[Copilot]

Pull Request Overview

This PR adds a new environment flag, AIO_DEV, to distinguish between local development and runtime environments.

• The change injects the AIO_DEV environment variable with a truthy string value ("true") when running locally with aio app dev.
• The change is implemented in the src/lib/run-dev.js file to enable environment detection during development.

[Copilot]

Consider checking if process.env.AIO_DEV is already set before overwriting it. This helps preserve any external overrides and makes the intent of the flag clearer.

Suggested change

	process.env.AIO_DEV = 'true'
	if (process.env.AIO_DEV === undefined) {
	process.env.AIO_DEV = 'true'
	}