feat(docker): the Swarm page is laid out by node: role, what its containers use, and the services placed on each (#5303)

#5303 "Swarm page laid out by node: role, resources and the tasks placed on each"

A verdict line first, then the nodes that are down or drained and the
services short of replicas, then one card per node. A node with a Steward
agent shows what its swarm tasks use against the machine's cores and memory,
service by service. A node without one lists Swarm's placement, by count.
The services table moved to the Docker overview, where it can be filtered.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

plugins/docker/swarm_nodes.py

@@ -0,0 +1,71 @@
+# plugins/docker/swarm_nodes.py
+"""The Swarm page laid out by node (#5303): one card per node with its role,
+whether it takes work, what its containers use against what the machine has,
+and the services Swarm placed on it. Model-free, so it is unit-tested without
+a database; routes.swarm() feeds it.
+
+A node with a Steward agent reports its own containers, so its services carry
+CPU and memory. A node without one is known only from the managers' placement:
+its services are listed by count, with no figures.
+"""
+from __future__ import annotations
+
+from .swarm_view import _placement
+
+
+def node_ok(n) -> bool:
+    """A node that is up and taking work."""
+    return n.status == "ready" and n.availability == "active"
+
+
+def node_cards(nodes, services, containers, *, node_host: dict, host_names: dict,
+               capacity: dict, service_state: dict) -> list[dict]:
+    """One card per node, a node in trouble first, then managers, then by name.
+
+    `nodes` and `services` are one swarm's deduplicated rows; `containers`
+    every container row (only running swarm tasks on these nodes count);
+    `node_host` maps a node id to the Steward host on it, `capacity` a host id
+    to (cores, memory bytes), `service_state` a service name to healthy,
+    degraded or down."""
+    running_on: dict[str, dict[str, dict]] = {}
+    for c in containers:
+        if not (c.node_id and c.service_name and c.status == "running"):
+            continue
+        row = running_on.setdefault(c.node_id, {}).setdefault(
+            c.service_name, {"name": c.service_name, "tasks": 0, "cpu_pct": 0.0, "mem_bytes": 0,
+                             "measured": True})
+        row["tasks"] += 1
+        row["cpu_pct"] += c.cpu_pct or 0.0
+        row["mem_bytes"] += c.mem_usage_bytes or 0
+    placed: dict[str, dict[str, int]] = {}
+    for s in services:
+        for p in _placement(s):
+            count = int(p.get("running") or 0)
+            if count > 0 and p.get("node_id"):
+                placed.setdefault(p["node_id"], {})[s.service_name] = count
+
+    cards = []
+    for n in nodes:
+        rows = dict(running_on.get(n.node_id, {}))
+        for name, count in placed.get(n.node_id, {}).items():
+            rows.setdefault(name, {"name": name, "tasks": count, "cpu_pct": None, "mem_bytes": None,
+                                   "measured": False})
+        for r in rows.values():
+            r["state"] = service_state.get(r["name"], "healthy")
+            r["cores"] = r["cpu_pct"] / 100 if r["cpu_pct"] is not None else None
+        tasks = sorted(rows.values(), key=lambda r: (r["state"] == "healthy", -(r["cores"] or 0.0),
+                                                     r["name"].lower()))
+        host_id = node_host.get(n.node_id)
+        cores, mem = capacity.get(host_id, (None, None)) if host_id else (None, None)
+        measured = [r for r in tasks if r["measured"]]
+        cards.append({
+            "node_id": n.node_id, "hostname": n.hostname or n.node_id[:12], "role": n.role,
+            "leader": n.leader, "status": n.status, "availability": n.availability, "ok": node_ok(n),
+            "host_id": host_id, "host_name": host_names.get(host_id) if host_id else None,
+            "agent": bool(running_on.get(n.node_id)) or host_id is not None,
+            "tasks": tasks, "task_count": sum(r["tasks"] for r in tasks),
+            "cores_used": sum(r["cores"] for r in measured) if measured else None,
+            "mem_used": sum(r["mem_bytes"] for r in measured) if measured else None,
+            "cores": cores, "mem": mem,
+        })
+    return sorted(cards, key=lambda c: (c["ok"], c["role"] != "manager", c["hostname"].lower()))