Better management of archived channel names

[chimnayajith]

Pull Request

Description

This PR improves archived stream support in the mobile app to match the web app’s behavior. Key updates include:

• Appending " (archived)" to stream names when viewing messages.
• Updating UI elements (e.g., stream headers) to clearly indicate archived streams.
• Filtering out archived channels from relevant pages.
• Displaying the archived tag in a distinct font and color, consistent with the web app.
• Replacing the compose box with a "no permission" error banner instead of offering message composition.

Related Issues

• Closes #800

Screenshots