ci(release): retry the Codeberg release create past the tag-settle 500

The Codeberg mirror step pushes the tag, then immediately POSTs the release
for it — but Codeberg 500s when the release request outruns its indexing of
the just-pushed ref, and with only one attempt that single 500 skipped the
mirror every release (the same POST succeeds seconds later, as a manual retry
confirmed for v2.16.0). Wrap the create/update in a backoff retry loop that
PATCHes in place if a release already exists, so a transient 5xx no longer
loses the mirror. Step stays best-effort (continue-on-error).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitea/workflows/release.yaml

@@ -412,20 +412,31 @@ jobs:
               "prerelease": False,
           }))
           PY
-          # Upsert (re-run safe). POST also creates the tag at target_commitish
-          # if the push mirror hasn't synced it yet.
-          ID=$(curl -s -H "Authorization: token $TOKEN" "$API/releases/tags/$TAG" | jq -r '.id // empty')
-          if [ -n "$ID" ]; then
-            curl -s -o /dev/null -w "release PATCH HTTP %{http_code}\n" -X PATCH \
+          # Create (or update) the release. Codeberg 500s on a POST/GET against a
+          # tag it has only just received — the release request outruns the
+          # indexing of the ref we pushed a moment ago — so a single attempt kept
+          # failing and skipping the mirror even though the very same call
+          # succeeds seconds later. Retry with backoff, and PATCH in place if a
+          # release already exists (re-run safe). A 5xx body still exits curl 0,
+          # so the loop, not `set -e`, controls the flow.
+          ID=""
+          for attempt in 1 2 3 4 5 6; do
+            EXIST=$(curl -s -H "Authorization: token $TOKEN" "$API/releases/tags/$TAG" | jq -r '.id // empty' 2>/dev/null || true)
+            if [ -n "$EXIST" ]; then
+              curl -s -o /dev/null -w "release PATCH HTTP %{http_code}\n" -X PATCH \
+                -H "Authorization: token $TOKEN" -H "Content-Type: application/json" \
+                -d @cb-payload.json "$API/releases/$EXIST"
+              ID="$EXIST"; break
+            fi
+            CODE=$(curl -s -o cb-response.json -w "%{http_code}" -X POST \
               -H "Authorization: token $TOKEN" -H "Content-Type: application/json" \
-              -d @cb-payload.json "$API/releases/$ID"
-          else
-            curl -s -o cb-response.json -w "release POST HTTP %{http_code}\n" -X POST \
-              -H "Authorization: token $TOKEN" -H "Content-Type: application/json" \
-              -d @cb-payload.json "$API/releases"
+              -d @cb-payload.json "$API/releases")
+            echo "release POST attempt $attempt HTTP $CODE"
             ID=$(jq -r '.id // empty' cb-response.json 2>/dev/null || true)
-          fi
-          if [ -z "$ID" ]; then echo "Could not resolve Codeberg release id." >&2; exit 1; fi
+            [ -n "$ID" ] && break
+            sleep $((attempt * 10))
+          done
+          if [ -z "$ID" ]; then echo "Could not resolve Codeberg release id after retries." >&2; exit 1; fi
 
           # Attach APK + checksum, replacing any prior asset of the same name.
           for A in "$ASSET_APK" "$ASSET_SUM"; do