fix: use until=1h filter for network prune in critical path

The critical disk prune path was doing `docker network prune -f`
without a filter, which removes ALL unused networks. This races with
Gitea Actions jobs that are mid-startup: the runner creates a network,
then the healthcheck prunes it before the container attaches, causing
"network not found" errors.

Use `--filter "until=1h"` (same as the warn path) to only remove
networks older than 1 hour.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

ansible/roles/gitea_runner/templates/runner-healthcheck.sh.j2

@@ -234,7 +234,10 @@ if [[ "$disk_pct" -ge {{ gitea_runner_healthcheck_disk_critical }} ]]; then
         | awk '{print $1}' \
         | xargs -r docker rm -f 2>/dev/null || true
     docker system prune -af --volumes || true
-    docker network prune -f || true
+    # Prune networks older than 1 hour only — removing ALL networks can
+    # race with Gitea Actions jobs that are mid-startup (network created
+    # but container not yet attached), causing "network not found" errors.
+    docker network prune -f --filter "until=1h" || true
     docker builder prune -af || true
     disk_pct=$(df -P / | awk 'NR==2 {gsub(/%/, "", $5); print $5}')
     echo "INFO: Disk usage after full prune: ${disk_pct}%"