Add demo scripts: egress IP check and bulk proxy creation

docs/demo/show-egress-ips.sh probes each healthy proxy from the
discovery API against an IP-echo site; create-kubernetes-proxies.sh and
create-gcp-proxies.sh bulk-create demo Proxies, the gcp one spreading
them across randomly picked EU zones.

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

docs/demo/create-gcp-proxies.sh

@@ -0,0 +1,94 @@
+#!/bin/bash
+# Demo: create N Managed proxies backed by the gcp provider, named
+# proxy-gcp-demo-1 .. proxy-gcp-demo-N, each in a randomly picked EU zone
+# so the fleet gets egress IPs from different locations.
+#
+# Usage:
+#   ./create-gcp-proxies.sh <count>
+#
+# Optional environment:
+#   NAMESPACE     namespace to create the proxies in (default: current context)
+#   GCP_PROVIDER  provider NAME from providers.yaml (default: gcp-eu)
+#   ZONES         space-separated zone list to pick from (default: EU zones below)
+set -euo pipefail
+
+if [ $# -ne 1 ] || ! [[ "$1" =~ ^[1-9][0-9]*$ ]]; then
+    echo "usage: $(basename "$0") <count>  (positive integer)" >&2
+    exit 1
+fi
+count="$1"
+provider="${GCP_PROVIDER:-gcp-eu}"
+
+# GCP zones in the EU where e2-micro is generally available. Override with
+# ZONES="zone1 zone2 ..." if your project has quota only in some of them.
+default_zones=(
+    europe-west1-b europe-west1-c europe-west1-d       # Belgium
+    europe-west2-a europe-west2-b europe-west2-c       # London
+    europe-west3-a europe-west3-b europe-west3-c       # Frankfurt
+    europe-west4-a europe-west4-b europe-west4-c       # Netherlands
+    europe-west6-a europe-west6-b europe-west6-c       # Zurich
+    europe-west8-a europe-west8-b europe-west8-c       # Milan
+    europe-west9-a europe-west9-b europe-west9-c       # Paris
+    europe-central2-a europe-central2-b europe-central2-c   # Warsaw
+    europe-north1-a europe-north1-b europe-north1-c    # Finland
+    europe-southwest1-a europe-southwest1-b europe-southwest1-c   # Madrid
+)
+if [ -n "${ZONES:-}" ]; then
+    read -r -a zones <<< "${ZONES}"
+else
+    zones=("${default_zones[@]}")
+fi
+
+if ! command -v kubectl &> /dev/null; then
+    echo "ERROR: kubectl is required but not installed" >&2
+    exit 1
+fi
+
+ns_args=()
+if [ -n "${NAMESPACE:-}" ]; then
+    ns_args=(-n "${NAMESPACE}")
+fi
+
+for i in $(seq 1 "${count}"); do
+    zone="${zones[RANDOM % ${#zones[@]}]}"
+    echo "Creating proxy-gcp-demo-${i} in ${zone} ..."
+    kubectl apply "${ns_args[@]}" -f - << EOF
+apiVersion: crawl.example.com/v1alpha1
+kind: Proxy
+metadata:
+  name: proxy-gcp-demo-${i}
+spec:
+  mode: Managed
+  provider: ${provider}              # must match a provider NAME in providers.yaml
+  placement:
+    zone: ${zone}
+    machineType: e2-micro
+    # debian-cloud images have no cloud-init, so spec.cloudInit (passed as
+    # user-data metadata) would be silently ignored there. Ubuntu images do.
+    image: projects/ubuntu-os-cloud/global/images/family/ubuntu-2404-lts-amd64
+  port: 3128
+  cloudInit:
+    inline: |
+      #cloud-config
+      package_update: true
+      packages:
+        - squid
+      write_files:
+        - path: /etc/squid/conf.d/proxy-operator.conf
+          content: |
+            http_access allow all
+            via off
+            forwarded_for off
+      runcmd:
+        - systemctl restart squid
+  attributes:
+    geo: eu
+    zone: ${zone}
+    purpose: crawl
+EOF
+done
+
+echo ""
+echo "Created ${count} proxies. VMs take a few minutes to provision and pass"
+echo "the health check. Watch them come up with:"
+echo "  kubectl get px ${ns_args[*]:-} -w"