Add remote agent config bundles and composite A2A support

[Codex]

Description

Decouple a2a_servers agent configs from code deploys by allowing startup to fetch a zipped config bundle (*_agent.toml) via A2A_AGENT_CONFIG_URL, with fallback to the existing directory-based loading, and merge the new composite agent support so a single A2A endpoint can front multiple Foundry agents.

Type of Change

• 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 not work as expected)
• Documentation update
• Code refactoring
• Performance improvement
• Test addition/improvement

Related Issues

Changes Made

• Add config_loader.py to resolve agent config location, download/extract .zip archives (http/https/file), and return the folder containing *_agent.toml.
• Wire __main__.py to prefer --agent-config-url/A2A_AGENT_CONFIG_URL, log the source, and load both regular and composite agent definitions.
• Document storage-based config hosting, Azure Blob setup, local/Dev Tunnel testing, composite behavior, and updated redeploy guidance across README and docs.
• Add targeted tests for the loader and composite/app factory flows, and refresh .env.template for the new env var.

Testing

• All existing tests pass
• Added new tests for new functionality
• Manually tested the changes
• Updated documentation

Checklist

• My code follows the project's style guidelines
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published

Screenshots (if applicable)

Additional Context

• Goal: enable editing/adding agent configs by updating a hosted archive instead of redeploying the app, while supporting composite A2A endpoints that front multiple Foundry agents.

[judacas]

@codex[agent] main has been updated with compound agents for the a2a. look at the new src/a2aServers that just got merged from the latest approved PR (#11 ) and update this to avoid conflicts and reflect the new status of the project

[chatgpt-codex-connector]

To use Codex here, create an environment for this repo.

[Codex]

@codex[agent] main has been updated with compound agents for the a2a. look at the new src/a2aServers that just got merged from the latest approved PR (#11 ) and update this to avoid conflicts and ref...

Updated branch with latest main (composite agents, tooling, docs) and reconciled remote config loader with composite discovery in 60112dd; tests now pass.