feat: add Cloudflare DNS tool suite with multi-instance support

- zone-list, record-list, record-create, record-update, record-delete
- Named instance support (-a flag) with configurable default
- Zone name-to-ID auto-resolution in shared _lib.sh
- Updated credentials loader with cloudflare/cloudflare-<name> services
- TOOLS.md and INFRASTRUCTURE.md guide documentation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tools/cloudflare/zone-list.sh

@@ -0,0 +1,59 @@
+#!/usr/bin/env bash
+#
+# zone-list.sh — List Cloudflare zones (domains)
+#
+# Usage: zone-list.sh [-a instance] [-f format]
+#
+# Options:
+#   -a instance   Cloudflare instance name (default: uses credentials default)
+#   -f format     Output format: table (default), json
+#   -h            Show this help
+set -euo pipefail
+
+MOSAIC_HOME="${MOSAIC_HOME:-$HOME/.config/mosaic}"
+source "$MOSAIC_HOME/tools/_lib/credentials.sh"
+source "$(dirname "$0")/_lib.sh"
+
+INSTANCE=""
+FORMAT="table"
+
+while getopts "a:f:h" opt; do
+  case $opt in
+    a) INSTANCE="$OPTARG" ;;
+    f) FORMAT="$OPTARG" ;;
+    h) head -10 "$0" | grep "^#" | sed 's/^# \?//'; exit 0 ;;
+    *) echo "Usage: $0 [-a instance] [-f format]" >&2; exit 1 ;;
+  esac
+done
+
+cf_load_instance "$INSTANCE"
+
+response=$(curl -s -w "\n%{http_code}" \
+  -H "Authorization: $(cf_auth)" \
+  -H "Content-Type: application/json" \
+  "${CF_API}/zones?per_page=50")
+
+http_code=$(echo "$response" | tail -n1)
+body=$(echo "$response" | sed '$d')
+
+if [[ "$http_code" != "200" ]]; then
+  echo "Error: Failed to list zones (HTTP $http_code)" >&2
+  echo "$body" | jq -r '.errors[]?.message // empty' 2>/dev/null >&2
+  exit 1
+fi
+
+if [[ "$FORMAT" == "json" ]]; then
+  echo "$body" | jq '.result'
+  exit 0
+fi
+
+echo "ZONE ID                           NAME                          STATUS    PLAN"
+echo "--------------------------------  ----------------------------  --------  ----------"
+echo "$body" | jq -r '.result[] | [
+  .id,
+  .name,
+  .status,
+  .plan.name
+] | @tsv' | while IFS=$'\t' read -r id name status plan; do
+  printf "%-32s  %-28s  %-8s  %s\n" "$id" "$name" "$status" "$plan"
+done