fix(backup): stream forgejo dump chunks via kubectl exec cat

kubectl cp still drops websocket on large forgejo dump parts; fall back
to exec cat with pod refresh and smaller 8m chunks.

tools/cmd/forgejo-backup

@@ -101,14 +101,29 @@ fi
 # Large dumps (~700M) fail via stdout stream or single kubectl cp — use chunks.
 dump_size="$(kubectl exec -n "${FORGEJO_NAMESPACE}" "${PROD_POD}" -c gitea -- \
   stat -c%s "${DUMP_REMOTE}" 2>/dev/null || echo 0)"
+refresh_prod_pod() {
+  PROD_POD="$(kubectl get pods -n "${FORGEJO_NAMESPACE}" \
+    -l "app.kubernetes.io/instance=${FORGEJO_RELEASE}" \
+    -o jsonpath='{.items[0].metadata.name}' 2>/dev/null || true)"
+}
+
 copy_from_pod() {
   local remote_path="$1" local_path="$2" attempt
-  for attempt in 1 2 3; do
+  for attempt in 1 2 3 4 5; do
+    refresh_prod_pod
+    if [[ -z "${PROD_POD}" ]]; then
+      sleep $((attempt * 5))
+      continue
+    fi
     if kubectl cp -n "${FORGEJO_NAMESPACE}" -c gitea \
       "${FORGEJO_NAMESPACE}/${PROD_POD}:${remote_path}" "${local_path}" 2>/dev/null; then
       return 0
     fi
-    sleep $((attempt * 3))
+    if kubectl exec --request-timeout=120 -n "${FORGEJO_NAMESPACE}" "${PROD_POD}" -c gitea -- \
+      cat "${remote_path}" > "${local_path}" 2>/dev/null && [[ -s "${local_path}" ]]; then
+      return 0
+    fi
+    sleep $((attempt * 5))
   done
   return 1
 }
@@ -118,8 +133,9 @@ if [[ "${dump_size}" -lt 52428800 ]]; then
 else
   ok "forgejo dump" "chunked copy (${dump_size} bytes)…"
   chunk_dir="$(mktemp -d)"
-  parts="$(kubectl exec -n "${FORGEJO_NAMESPACE}" "${PROD_POD}" -c gitea -- \
+  refresh_prod_pod
-    sh -c "split -b 16m '${DUMP_REMOTE}' /tmp/forgejo-backup-part- && ls /tmp/forgejo-backup-part-*")"
+  parts="$(kubectl exec --request-timeout=120 -n "${FORGEJO_NAMESPACE}" "${PROD_POD}" -c gitea -- \
+    sh -c "rm -f /tmp/forgejo-backup-part-*; split -b 8m '${DUMP_REMOTE}' /tmp/forgejo-backup-part- && ls /tmp/forgejo-backup-part-*")"
   for part in ${parts}; do
     base="$(basename "${part}")"
     copy_from_pod "${part}" "${chunk_dir}/${base}" || { bad "forgejo dump" "chunk copy failed: ${base}"; exit 1; }