Adding additional events to ContentType + Add CODEOWNERS file

[mliao95]

Issue Number:

Description:

What are the changes? Why are we making them?

This PR updates the list of chat events to cover additional scenarios such as authentication, idle, transfers and chat re-hydration.

This PR also adds a CODEOWNERS file so that reviewers are auto-assigned upon PR creation.

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Functional backward compatibility:

Does this change introduce backwards incompatible changes? [YES/NO]

NO

Does this change introduce any new dependency? [YES/NO]

NO

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Testing:

Is the code unit tested?

NA

Have you tested the changes with a sample UI (e.g. Android Mobile Chat Example)?

NA

List manual testing steps:

• Add Steps below:

Here are a list of manual test cases to run through:

• Initiating chat and connecting with an agent
• Retrieving transcript
• Disconnecting from chat
• Sending a message to the agent
  • See typing bubbles on agent side
  • See read/delivered receipt on client side
  • Receiving a message from the agent
  • See typing bubbles on client side
  • See read/delivered receipt on agent side
  • Sending an attachment to the agent (try .txt, .pdf, .jpg)
  • Preview the attachment on click
  • Receiving an attachment from the agent
  • Preview the attachment on click
• Close the application (Without ending chat) → open app again → Start chat → Should Retrieve transcript from a previous chat session

[Copilot]

Pull Request Overview

This PR extends the ContentType enum to support additional chat-related events such as authentication events, participant state changes, transfer events, and chat rehydration.

• Added several new ContentType enum values to cover the expanded event list.
• Updated the enum formatting from a semicolon after the original list to a comma-separated list followed by a semicolon on the final entry.

Comments suppressed due to low confidence (1)

chat-sdk/src/main/java/com/amazon/connect/chat/sdk/model/ContentType.kt:36

• [nitpick] Consider adding unit tests to validate the mapping of ContentType enum values, particularly for the newly added events.

companion object {