Added Favicon to header and corrected package manager list

[EntityDeleter]

I thought it would be a good idea to include the logo at the top as well, near the title "llama.app".

I also fixed the part where it said "Prefer Brew or Winget?" and added Nix and MacPorts.

Also fixed a few issues my LSP was whining about in Zed, mainly that bg-foreground/[0.04] could be written as bg-foreground/4 in a few places.

This is my first commit to a public repository that is not niche, so please direct me if I have done something wrong. Thank you!

[EntityDeleter]

A few more additions:

• Added Qwen3.5 4B for a similar competing model to Gemma4
• Swapped the images/animations in the first and third rows with the text
• Found that the large favicon at the top used an inline SVG, changed it to refer to the asset
• On smaller monitors (1280 x 1024) the "Apple Silicon" would overflow and be cut off. Can also be resolved by replacing whitespace-nowrap with wrap-break-word for the container. Widened container width. Reverted, causes misalignment.