fix(release): parse release id robustly and validate upload endpoint

Use JSON parsing for release id extraction in publish action instead of
regex matching, preventing wrong id selection from nested fields.
Add a pre-upload release endpoint check to fail early with explicit
release URL diagnostics when the resolved id/path is invalid.

.gitea/workflows/prepare-release.yml

@@ -275,6 +275,15 @@ jobs:
             exit 1
           fi
 
+          release_detail_api="${GITHUB_API_URL:-${GITHUB_SERVER_URL%/}/api/v1}/repos/${GITHUB_REPOSITORY}/releases/${release_id}"
+          if ! curl --fail-with-body -sS \
+            -H "Authorization: token ${RELEASE_TOKEN}" \
+            -H "Content-Type: application/json" \
+            "$release_detail_api" >/dev/null; then
+            echo "Resolved release endpoint is not accessible: ${release_detail_api}" >&2
+            exit 1
+          fi
+
           release_api="${GITHUB_API_URL:-${GITHUB_SERVER_URL%/}/api/v1}/repos/${GITHUB_REPOSITORY}/releases/${release_id}/assets"
 
           for asset in dist/*; do