Fix release workflow: fetch git tags for changelog generation

actions/checkout@v4 does not fetch tags by default, causing the
previous tag lookup to fail and fall back to comparing with the
first commit SHA. Added fetch-depth: 0 to fetch all history including tags.

.github/workflows/release.yml

@@ -117,6 +117,8 @@ jobs:
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
+        with:
+          fetch-depth: 0  # Fetch all history for tags
 
       - name: Set up Go
         uses: actions/setup-go@v5