docs: Only do vercel preview on docs change (#3822)

* docs: Only do vercel preview on docs change

* docs: fix malformed frontmatter

docs/content/docs/updates/release-notes/0-30-1.mdx

@@ -1,4 +1,4 @@
-   ---
+---
 title: 0.30.1
 description: Anchor - Release Notes 0.30.1
 ---

docs/vercel.sh

@@ -1,13 +1,17 @@
 #!/bin/bash
 
-git diff --quiet HEAD^ HEAD ./
-has_changes=$?
-echo ">> Diff status $has_changes"
+# Check if there are changes in the docs directory
+git diff --quiet HEAD^ HEAD -- ../docs/
+has_docs_changes=$?
+echo ">> Docs diff status $has_docs_changes"
 
-if [[ $VERCEL_GIT_COMMIT_REF == "master" ]] || [ $has_changes == 1 ]; then
+# Deploy if:
+# 1. It's the master branch (production deployment), OR
+# 2. There are changes in the docs directory (preview deployment)
+if [[ $VERCEL_GIT_COMMIT_REF == "master" ]] || [ $has_docs_changes == 1 ]; then
   echo ">> Proceeding with deployment."
   exit 1;
 else
-  echo ">> Skipping deployment."
+  echo ">> Skipping deployment (no docs changes detected)."
   exit 0;
 fi