feat(v5): sync server status and ingress access

Add Flux agent token issuing, open and revoke Caddy ingress firewall
rules, broadcast server-scoped application status updates, and update
the dashboard to show unreachable servers as unknown.

tests/Scripts/dev-shell-test.sh

@@ -0,0 +1,78 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+TMP_DIR="$(mktemp -d)"
+trap 'rm -rf "$TMP_DIR"' EXIT
+
+mkdir -p "$TMP_DIR/bin"
+cat > "$TMP_DIR/bin/limactl" <<'STUB'
+#!/usr/bin/env bash
+set -euo pipefail
+
+case "${1:-}" in
+  list)
+    cat <<'LIST'
+NAME          STATUS
+coold-dev     Running
+coold-dev-2   Running
+LIST
+    ;;
+  shell)
+    printf '%s\n' "$*" > "$LIMACTL_SHELL_ARGS_FILE"
+    ;;
+  *)
+    printf '%s\n' "$*" > "${LIMACTL_OTHER_ARGS_FILE:-/dev/null}"
+    ;;
+esac
+STUB
+chmod +x "$TMP_DIR/bin/limactl"
+
+export PATH="$TMP_DIR/bin:$PATH"
+export LIMACTL_SHELL_ARGS_FILE="$TMP_DIR/limactl-shell-args"
+export LIMACTL_OTHER_ARGS_FILE="$TMP_DIR/limactl-other-args"
+
+assert_equals() {
+  local expected="$1"
+  local actual="$2"
+  local message="$3"
+
+  if [ "$expected" != "$actual" ]; then
+    echo "FAIL: $message" >&2
+    echo "Expected: $expected" >&2
+    echo "Actual:   $actual" >&2
+    exit 1
+  fi
+}
+
+assert_contains() {
+  local needle="$1"
+  local haystack="$2"
+  local message="$3"
+
+  if [[ "$haystack" != *"$needle"* ]]; then
+    echo "FAIL: $message" >&2
+    echo "Expected output to contain: $needle" >&2
+    echo "Actual output: $haystack" >&2
+    exit 1
+  fi
+}
+
+(
+  cd "$ROOT"
+  scripts/dev.sh shell coold-dev-2 >/dev/null
+)
+assert_equals "shell coold-dev-2 -- sudo env TERM=xterm-256color SYSTEMD_PAGER=cat SYSTEMD_LESS=FRXMK bash -l" "$(cat "$LIMACTL_SHELL_ARGS_FILE")" "shell accepts a Lima hostname"
+
+set +e
+numeric_output="$(cd "$ROOT" && scripts/dev.sh shell 1 2>&1 >/dev/null)"
+numeric_status=$?
+set -e
+
+if [ "$numeric_status" -eq 0 ]; then
+  echo "FAIL: numeric shell target should be rejected" >&2
+  exit 1
+fi
+assert_contains "Use the Lima hostname" "$numeric_output" "numeric shell target explains hostname usage"
+
+echo "dev-shell-test: ok"