fix(ci): use container name 'portainer' instead of IP

All services (Gitea, the 3 runners and Portainer itself) are in the
same Docker network 'portainer_default', so the service name 'portainer'
resolves directly from inside any container in that network. The previous
auto-discovery dance with IPs and routes is no longer needed.

- Set the PORTAINER_URL secret to 'http://portainer:9000'.
- Replace the entire 'Step 0' auto-discovery with a simple check that
  the configured URL is reachable.
- Drop the debug Step 0a that was added during troubleshooting.

The runner's job container can now reach Portainer the same way the
runner itself does — by name.

.gitea/workflows/ci-cd.yaml

@@ -65,64 +65,18 @@ jobs:
       - name: Redeploy stack on Portainer
         if: github.event_name == 'workflow_dispatch' && inputs.deploy == true
         env:
+          PORTAINER_URL: ${{ secrets.PORTAINER_URL }}
           PORTAINER_TOKEN: ${{ secrets.PORTAINER_TOKEN }}
           PORTAINER_ENDPOINT_ID: ${{ secrets.PORTAINER_ENDPOINT_ID }}
           PORTAINER_STACK_ID: ${{ secrets.PORTAINER_STACK_ID }}
         run: |
-          # NOTE: no `set -e` here on purpose — the auto-discovery loop below
+          # Portainer, Gitea and the runners all share the `portainer_default`
-          # needs to try every candidate even if some probes fail, and some
+          # Docker network on the NAS, so the service name "portainer" resolves
-          # diagnostic commands (ip route, hostname -I) might return empty
+          # directly from the job container. No need for IP auto-discovery.
-          # in unusual container network setups without aborting the job.
+          echo "Using PORTAINER_URL=$PORTAINER_URL"
-          echo "hostname: $(hostname)"
+          if ! curl -sS -o /dev/null -w '%{http_code}' --max-time 5 \
-          echo "hostname -I:"
+              "${PORTAINER_URL}/api/status" | grep -q '^200$'; then
-          hostname -I 2>/dev/null || echo "(none)"
+            echo "ERROR: Portainer not reachable at $PORTAINER_URL" >&2
-          echo "ip -4 addr show (eth* only):"
-          ip -4 addr show 2>/dev/null | grep -E "^[0-9]+:|inet " | head -20
-          echo "ip route:"
-          ip route 2>/dev/null
-          echo "ip route show default:"
-          ip -4 route show default 2>/dev/null
-          echo "curl to 192.168.1.30:9000 (5s timeout):"
-          curl -sS -o /dev/null -w '  HTTP=%{http_code} time=%{time_total}s\n' --max-time 5 "http://192.168.1.30:9000/api/status" 2>&1 || echo "  (curl failed)"
-          echo "---"
-
-          echo "--- Step 0: auto-discover a reachable Portainer URL ---"
-          # The runner creates an ephemeral docker network per job, so the
-          # canonical PORTAINER_URL (e.g. http://192.168.1.30:9000) often isn't
-          # reachable from inside the job container. Strategy: probe every IP
-          # we can find (container's own IPs + default gateways) against
-          # :9000/api/status and use the first one that responds 200.
-          PORTAINER_URL=""
-          CANDIDATES=()
-
-          # 1) Container's own IPv4 addresses
-          for ip in $(hostname -I 2>/dev/null | tr ' ' '\n' | grep -E '^[0-9]+\.'); do
-            CANDIDATES+=("http://${ip}:9000")
-          done
-
-          # 2) Default gateways of every default route
-          while IFS= read -r gw; do
-            [ -n "$gw" ] && CANDIDATES+=("http://${gw}:9000")
-          done < <(ip -4 route show default 2>/dev/null | awk '{print $3}' | sort -u)
-
-          # 3) Fallback: secret value (in case everything else fails)
-          CANDIDATES+=("${{ secrets.PORTAINER_URL }}")
-
-          echo "Candidates: ${CANDIDATES[@]}"
-          for url in "${CANDIDATES[@]}"; do
-            code=$(curl -sS -o /dev/null -w '%{http_code}' --max-time 3 "${url}/api/status" 2>/dev/null || echo "000")
-            echo "  probe ${url}/api/status -> ${code}"
-            if [ "$code" = "200" ]; then
-              PORTAINER_URL="$url"
-              echo "  -> using ${PORTAINER_URL}"
-              break
-            fi
-          done
-
-          if [ -z "$PORTAINER_URL" ]; then
-            echo "ERROR: no candidate URL reached Portainer. Tried: ${CANDIDATES[@]}" >&2
-            echo "ERROR: container hostname=$(hostname) IP=$(hostname -I)" >&2
-            echo "ERROR: ip route=$(ip route 2>&1 | tr '\n' ';')" >&2
             exit 1
           fi