[docs] Fix MD028 blank line between blockquotes in getting-started guide

Removes blank line between WARNING and IMPORTANT blockquotes that was
failing markdownlint across all PRs.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: jaredirish

docs/01-getting-started.md

@@ -242,7 +242,7 @@ Copy the output — it'll look something like `a3f8b2c1d4e5...` (64 characters).
 
 > [!WARNING]
 > Copy and paste the command for **your operating system only**. The Mac command won't work on Windows and vice versa.
-
+>
 > [!IMPORTANT]
 > This is your **one access key for all of Open Brain** — core setup and every extension you add later. Save it somewhere permanent. Never generate a new one unless you want to replace it for ALL deployed functions.