UI: Implement Standardized Chat Bubble Alignment and Constraints

[Sarthak45-del]

Is your feature request related to a problem?

• Yes, it is related to a problem

Describe the feature you'd like

🔍 Problem
Currently, the chat bubbles in the chat interface lack proper alignment logic. Specifically:

1. Messages from the user and the assistant/others are not clearly aligned to opposite sides (Left vs. Right).

2. The padding inside the bubbles and the margins between bubbles are inconsistent on different screen sizes.

3. Long messages stretch across the full width, making them hard to read.

💡 Proposed Solution
I would like to refactor the ChatBubble widget to use:

1. An Align widget based on the sender's identity.

2. BoxConstraints to limit the maxWidth to roughly 75-80% of the screen.

3. Consistent EdgeInsets for better readability.

I have a local fix ready and would like to be assigned to this.

Record

• I agree to follow this project's Code of Conduct
• I want to work on implementing this feature