Fix CI: release grep exit code, golangci-lint v2 config version

Release pipeline crashed when no prior release existed because
grep returned exit 1 (no match) under set -e. Add || true.

golangci-lint v2 requires a version: "2" field in .golangci.yml.

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

.gitea/workflows/release.yml

@@ -97,7 +97,7 @@ jobs:
           # Delete existing release for this tag (re-release support)
           EXISTING=$(curl -s "${API}/releases/tags/${TAG}" \
             -H "Authorization: token ${TOKEN}" \
-            | grep -o '"id":[0-9]*' | grep -m1 -o '[0-9]*')
+            | grep -o '"id":[0-9]*' | grep -m1 -o '[0-9]*' || true)
           if [ -n "$EXISTING" ]; then
             curl -s -X DELETE "${API}/releases/${EXISTING}" \
               -H "Authorization: token ${TOKEN}"

.golangci.yml

@@ -1,3 +1,5 @@
+version: "2"
+
 linters:
   enable:
     - errcheck