Add font size adjustment option and fix inconsistent font size/spacing in chat window

[bobleer]

Problem Description

Users currently have two related concerns regarding text display in the application:

1. No font size adjustment option: Users have no option to adjust the font size in the appearance settings. Different users have different visual preferences and needs, and the inability to customize font size makes it difficult for users with vision impairments or those who simply prefer larger/smaller text to use the app comfortably.

2. Inconsistent font size and spacing in chat window: The chat window displays messages with inconsistent font sizes and spacing. This creates a visually cluttered and unprofessional appearance, making the conversation difficult to read and follow.

Expected Behavior

1. Provide a font size adjustment slider or option in the appearance/settings menu

   • Allow users to preview changes in real-time
   • Remember user's font size preference

2. Consistent font size across all messages

   • Consistent line spacing and message padding
   • Proper alignment of messages

Actual Behavior

1. No font size customization option available in settings
2. Font sizes vary between messages unexpectedly
3. Line spacing is irregular
4. Message margins/padding are inconsistent

Use Case Scenarios

• Users with vision impairments need larger text
• Users prefer smaller text to see more content on screen
• Users want a cleaner, more consistent chat experience
• Users simply want to customize their reading experience