fix(docs): missing line breaks in why-base page cause text to run together

**Page:** https://docs.base.org/base-chain/quickstart/why-base
**File:** `docs/base-chain/quickstart/why-base.mdx`

## Description

Two bullet points in the body text are missing a line break, causing them to run into the next paragraph.

**First occurrence** – "A platform for building innovative apps" section:

> - Accept payments from anyone, easilyIt's fast, cheap, and permissionless...

**Second occurrence** – "Expansive developer tools" section:

> - Robust developer toolingBut there's more: ...

## Expected behavior

Each bullet point should end before the following sentence begins, e.g.:

```
- Accept payments from anyone, easily

It's fast, cheap, and permissionless...
```

## Steps to reproduce

1. Visit https://docs.base.org/base-chain/quickstart/why-base
2. Look at the bullet list under "A platform for building innovative apps"
3. The last bullet item runs directly into the next paragraph without a line break

## Suggested fix

Add a blank line (or move the continuation text outside the list block) after each affected bullet item in the MDX source.