Stage 17 (#15): admin users people/robots toggle + display-name & external-id glob filters

- account.ListUsers/CountUsers with a UserFilter: people vs robots (by a robot identity),
  case-insensitive '*'/'?' glob masks on display_name and any identity's external_id
- admin users list shows the real kind (robot/guest/registered), defaults to people,
  with a People/Robots toggle + a filter form; pager preserves the filter
- integration test for the filter; SQL verified against the live contour DB

backend/internal/inttest/userlist_test.go

@@ -0,0 +1,86 @@
+//go:build integration
+
+package inttest
+
+import (
+	"context"
+	"testing"
+
+	"github.com/google/uuid"
+
+	"scrabble/backend/internal/account"
+)
+
+// TestUserListFilter checks the admin user-list filter: the people/robots split (by a
+// robot identity) and the case-insensitive glob masks on display name and external id.
+func TestUserListFilter(t *testing.T) {
+	ctx := context.Background()
+	st := account.NewStore(testDB)
+	uniq := uuid.NewString()
+
+	human, err := st.ProvisionTelegram(ctx, "tg-"+uniq, "en", "", "Zzqxhuman")
+	if err != nil {
+		t.Fatalf("provision human: %v", err)
+	}
+	robot, err := st.ProvisionRobot(ctx, "robot-uxz-"+uniq, "Zzqxbot")
+	if err != nil {
+		t.Fatalf("provision robot: %v", err)
+	}
+	guest, err := st.ProvisionGuest(ctx)
+	if err != nil {
+		t.Fatalf("provision guest: %v", err)
+	}
+
+	collect := func(f account.UserFilter) map[uuid.UUID]account.UserListItem {
+		items, err := st.ListUsers(ctx, f, 5000, 0)
+		if err != nil {
+			t.Fatalf("list users %+v: %v", f, err)
+		}
+		m := make(map[uuid.UUID]account.UserListItem, len(items))
+		for _, it := range items {
+			m[it.ID] = it
+		}
+		return m
+	}
+
+	people := collect(account.UserFilter{})
+	if _, ok := people[human.ID]; !ok {
+		t.Error("human missing from people")
+	}
+	if _, ok := people[guest.ID]; !ok {
+		t.Error("guest missing from people")
+	}
+	if _, ok := people[robot.ID]; ok {
+		t.Error("robot must not appear in people")
+	}
+	if it := people[human.ID]; it.IsRobot || it.IsGuest {
+		t.Errorf("human flags wrong: robot=%v guest=%v (want both false)", it.IsRobot, it.IsGuest)
+	}
+
+	robots := collect(account.UserFilter{Robots: true})
+	if it, ok := robots[robot.ID]; !ok || !it.IsRobot {
+		t.Errorf("robot missing from robots or IsRobot=false (ok=%v)", ok)
+	}
+	if _, ok := robots[human.ID]; ok {
+		t.Error("human must not appear in robots")
+	}
+
+	// Name mask (people).
+	if _, ok := collect(account.UserFilter{NameMask: "Zzqx*"})[human.ID]; !ok {
+		t.Error("name mask Zzqx* should match the human")
+	}
+	if _, ok := collect(account.UserFilter{NameMask: "nomatch*"})[human.ID]; ok {
+		t.Error("name mask nomatch* should not match the human")
+	}
+	// External-id mask (robots).
+	if _, ok := collect(account.UserFilter{Robots: true, ExternalIDMask: "robot-uxz-*"})[robot.ID]; !ok {
+		t.Error("external-id mask robot-uxz-* should match the robot")
+	}
+	if _, ok := collect(account.UserFilter{Robots: true, ExternalIDMask: "robot-zzz-*"})[robot.ID]; ok {
+		t.Error("external-id mask robot-zzz-* should not match the robot")
+	}
+	// CountUsers agrees that robots exist.
+	if n, err := st.CountUsers(ctx, account.UserFilter{Robots: true, ExternalIDMask: "robot-uxz-*"}); err != nil || n != 1 {
+		t.Errorf("count robots robot-uxz-* = (%d, %v), want 1", n, err)
+	}
+}