fix(site): rebalance hero install layout

[fcoury]

Why

The desktop hero lets the tagline overpower the Red wordmark, and the macOS/Linux curl command can push the copy action outside the install control.

What

• enlarge the responsive ASCII wordmark and lower the hero headline ceiling
• widen the install control for the full curl command
• keep the prompt and copy action fixed while allowing command text to truncate safely on narrow screens
• contain the entire control so it cannot create horizontal page overflow

How to Test

1. Open the hero around 1839×1382, select macOS + Linux, and confirm the wordmark is taller than the two-line headline and the full curl command plus copy action remain inside the control.
2. Resize to 390×844 and confirm the page has no horizontal overflow; the command may ellipsize while the copy action remains visible.
3. Run npm test and npm run lint; both must pass.