Fix mirror-pr workflow failing on PR bodies with special characters

GitHub Actions expands ${{ }} expressions before the shell runs, so
backticks and $ signs in PR bodies were injected raw into the script
and interpreted as shell command substitution.

Fix: write static content via a single-quoted heredoc (no shell
expansion), then append the PR body via printf with an env var
($PR_BODY). Shell variables accessed as "$VAR" are never
re-interpreted, making any PR body content safe.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: sharadregoti

.github/workflows/mirror-pr-to-build-deploy.yml

@@ -32,26 +32,28 @@ jobs:
             # Create new mirror PR
             echo "Creating new mirror PR..."
           
-            # Create PR body content using printf to avoid shell parsing issues
-            printf '%s\n' \
-              "**🔗 Auto-generated mirror PR for Mintlify preview**" \
-              "" \
-              "**Original PR:** #${{ github.event.number }}" \
-              "**Author:** @${{ github.event.pull_request.user.login }}" \
-              "" \
-              "## Purpose" \
-              "This PR provides a Mintlify preview link for reviewing documentation changes." \
-              "" \
-              "## Preview Link" \
-              "The Mintlify preview will be available once this PR is processed." \
-              "" \
-              "## ⚠️ Important Notes" \
-              "- **Do not merge this PR directly**" \
-              "- This PR will be auto-merged when the original PR #${{ github.event.number }} is merged" \
-              "- Make all comments and reviews on the original PR #${{ github.event.number }}" \
-              "" \
-              "## Changes" \
-              "${{ github.event.pull_request.body }}" > pr_body.txt
+            # Write PR body to file via env var to safely handle special characters
+            # (backticks, $, quotes) without shell re-interpretation
+            cat > pr_body.txt << 'ENDBODY'
+**🔗 Auto-generated mirror PR for Mintlify preview**
+
+**Original PR:** #${{ github.event.number }}
+**Author:** @${{ github.event.pull_request.user.login }}
+
+## Purpose
+This PR provides a Mintlify preview link for reviewing documentation changes.
+
+## Preview Link
+The Mintlify preview will be available once this PR is processed.
+
+## ⚠️ Important Notes
+- **Do not merge this PR directly**
+- This PR will be auto-merged when the original PR #${{ github.event.number }} is merged
+- Make all comments and reviews on the original PR #${{ github.event.number }}
+
+## Changes
+ENDBODY
+            printf '%s\n' "$PR_BODY" >> pr_body.txt
 
             # Escape the title properly to handle special characters and spaces
             ESCAPED_TITLE=$(printf '%s' "🔄 Preview: ${{ github.event.pull_request.title }}" | sed 's/"/\\"/g')
@@ -69,6 +71,7 @@ jobs:
           fi
         env:
           GH_TOKEN: ${{ secrets.ORG_GH_TOKEN }}
+          PR_BODY: ${{ github.event.pull_request.body }}
 
   cleanup-mirror-pr:
     runs-on: ubuntu-latest