Learn per-model context from /props?model=; only status "loaded" is loaded

Implemented-By: OpenCode session (model recorded in docs/implementer-log.md)

internal/admin/admin_models_test.go

@@ -0,0 +1,46 @@
+package admin_test
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+
+	"git.wntrmute.dev/kyle/crossbar/internal/admin"
+	"git.wntrmute.dev/kyle/crossbar/internal/health"
+)
+
+// The hosts view shows the per-model context the poller learned, and an empty object (never
+// null) for a host with nothing learned.
+func TestHostsShowsPerModelContext(t *testing.T) {
+	r := newRig(t)
+	r.hosts.st["alpha"] = health.Status{
+		Healthy: true,
+		Loaded:  []string{"m"},
+		NCtx:    0, // a router: the host-level figure stays unknown
+		Models:  map[string]health.ModelCtx{"m": {NCtx: 65536, Slots: 2}},
+	}
+	rec := r.do(t, "GET", "/_crossbar/hosts", "")
+	if rec.Code != 200 {
+		t.Fatalf("%d %s", rec.Code, rec.Body.String())
+	}
+	var out map[string]admin.HostView
+	if err := json.Unmarshal(rec.Body.Bytes(), &out); err != nil {
+		t.Fatal(err)
+	}
+	if got := out["alpha"].Models["m"]; got != (health.ModelCtx{NCtx: 65536, Slots: 2}) {
+		t.Errorf("alpha.models[m] = %+v, want {65536 2}", got)
+	}
+	if out["alpha"].NCtx != 0 {
+		t.Errorf("alpha.n_ctx = %d, want 0 (unknown at host level on a router)", out["alpha"].NCtx)
+	}
+	var raw map[string]json.RawMessage
+	if err := json.Unmarshal(rec.Body.Bytes(), &raw); err != nil {
+		t.Fatal(err)
+	}
+	if beta := string(raw["beta"]); !strings.Contains(beta, `"models":{}`) {
+		t.Errorf("beta = %s, want \"models\":{} (never null)", beta)
+	}
+	if alpha := string(raw["alpha"]); !strings.Contains(alpha, `"models":{"m":{"n_ctx":65536,"slots":2}}`) {
+		t.Errorf("alpha = %s, want models keyed by id with n_ctx and slots", alpha)
+	}
+}