Add proactive samples for JavaScript and Python

[Joel Mut (sw-joelmut)]

Addresses #682

Description

This PR adds customer-facing proactive samples for JavaScript and Python and aligns the existing .NET sample with the same experience. The samples show how to store a conversation, send an activity later, continue a conversation from saved data, and export conversation data for an HTTP request.

The three samples now use the same sample name, commands, route names, welcome content, manifest structure, and customer documentation.

Changes

Proactive samples

• Add the JavaScript proactive sample.
• Add the Python proactive sample.
• Align the existing .NET proactive sample with JavaScript and Python.
• Add the same commands in all languages:
  • -s
  • -c
  • -c <conversation-id>
  • -convo
  • proactive echo for other text
• Add POST /proactive/sendActivity/{conversationId}.
• Add POST /proactive/continue.

Customer experience and documentation

• Add a left-aligned Adaptive Card welcome message.
• Improve command descriptions and stored-conversation guidance.
• Add aligned README files, environment templates, Teams manifests, and route response guidance.
• Document customer security requirements for proactive HTTP routes and caller authorization.
• Add the proactive sample parity report.

Configuration and cleanup

• Align proactive route authentication behavior across the samples.
• Add the required Python Bot Framework scope configuration.
• Remove Playground-only behavior from the shipped samples.

Testing

The proactive flow was tested manually in Microsoft 365 Agents Playground for JavaScript and .NET. The tests covered the welcome message, -s, both -c forms, -convo, proactive echo, sendActivity, and continue.

The following images show the tested .NET, JavaScript, and Python proactive flows: