[FEAT] Add Curved Design Variant + Customization

[Spiral-Memory]

As an EmbeddedChat developer,

I need to:

• Add a curved design variant with bubble chat
• Implement different chat header and input designs
• Make things customizable

So that:

• Users can choose their desired designs

Acceptance Criteria:

• [x] Addition of curved designs

[Spiral-Memory]

Hey @sidmohanty11 Please add the required labels to this issue. Thanks !