feat: add voice message duration display to VoiceMessageView

[Copilot]

Description

Voice messages support voiceMessageDuration parameter in the Message model but the duration wasn't rendered in the VoiceMessageView widget. Duration was only visible in reply message previews.

Changes:

• VoiceMessageView widget: Added conditional Text widget to display voiceMessageDuration after the waveform using the existing toHHMMSS() extension
• VoiceMessageConfiguration: Added optional durationTextStyle parameter for styling customization (defaults to 12px white text)
• Documentation: Added usage examples in doc/documentation.md

Usage:

Message(
  id: '1',
  message: '/path/to/audio.m4a',
  createdAt: DateTime.now(),
  sentBy: userId,
  messageType: MessageType.voice,
  voiceMessageDuration: Duration(seconds: 15), // Now displays in bubble
)

Customize appearance via configuration:

VoiceMessageConfiguration(
  durationTextStyle: TextStyle(fontSize: 12, color: Colors.white),
)

Checklist

• The title of my PR starts with a Conventional Commit prefix (fix:, feat:, docs: etc).
• I have followed the Contributor Guide when preparing my PR.
• I have updated/added tests for ALL new/updated/fixed functionality.
• I have updated/added relevant documentation in docs and added dartdoc comments with ///.
• I have updated/added relevant examples in examples or docs.

Breaking Change?

• Yes, this PR is a breaking change.
• No, this PR is not a breaking change.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>issue in voice messge duration</issue_title>
<issue_description>
how can I display the voice message duration , I already passed the duration into the message model
Message(
id: id?.toString() ?? '',
message: chatViewMessageType == MessageType.text
? (message ?? '')
: (file ?? ''),
createdAt: parsedDate ?? DateTime.now(),
sentBy: sender?.id?.toString() ?? '',
messageType: chatViewMessageType,
voiceMessageDuration:Duration(seconds: 15) // test

and when voice is displayed there is no duration appears
is there any step missed??
</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes issue in voice messge duration #426

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[Copilot]

Pull request overview

This PR adds visible duration display for voice messages in the main chat bubble, leveraging the existing voiceMessageDuration field and the toHHMMSS() extension, and exposes configuration to style that duration text along with documentation updates.

Changes:

• Update VoiceMessageView to render voiceMessageDuration next to the waveform when present, formatted via toHHMMSS().
• Extend VoiceMessageConfiguration with an optional durationTextStyle to customize the duration label appearance.
• Document voice message duration usage and styling in doc/documentation.md, including examples for message creation and configuration.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
lib/src/widgets/voice_message_view.dart	Renders the voice message duration text conditionally after the waveform, using VoiceMessageConfiguration.durationTextStyle with a sensible default.
lib/src/models/config_models/voice_message_configuration.dart	Adds the new durationTextStyle field to the configuration model and documents its purpose.
doc/documentation.md	Adds a new “Voice Message Duration” section and updates the voice message configuration example to show how to style the duration label.

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