Web UI: administrators make tokens for other users

New token on a user's row under Users, with the Account page's dialog
(now tokenDialog in users.js), offering only roles within that user's
permissions.

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

internal/server/server_test.go

@@ -1335,3 +1335,30 @@ func TestCreatePlaced(t *testing.T) {
 		t.Errorf("%d rules", n)
 	}
 }
+
+// TestTokenForUser: an administrator makes a token for another user (the
+// web UI's New token on a user's row); that user can't make one for
+// someone else.
+func TestTokenForUser(t *testing.T) {
+	e := newEnv(t)
+	var u api.User
+	if code := e.call(e.token, "POST", "/users", api.UserInput{Username: ptr("portal"), Grants: &[]string{"sets:write"}}, &u); code != 201 {
+		t.Fatalf("user: %d", code)
+	}
+	var tok api.Token
+	if code := e.call(e.token, "POST", "/users/"+itoa(u.ID)+"/tokens", api.TokenInput{Name: "portal", ExpiresIn: "30d"}, &tok); code != 201 || tok.Secret == "" || tok.UserID != u.ID {
+		t.Fatalf("token for portal: %d %+v", code, tok)
+	}
+	if code := e.call(tok.Secret, "GET", "/rules", nil, nil); code != 403 {
+		t.Errorf("the token can do more than its user: %d", code)
+	}
+	var users []api.User
+	e.call(e.token, "GET", "/users", nil, &users)
+	for _, o := range users {
+		if o.ID != u.ID {
+			if code := e.call(tok.Secret, "POST", "/users/"+itoa(o.ID)+"/tokens", api.TokenInput{Name: "x"}, nil); code != 403 {
+				t.Errorf("a token for another user, made by a non-administrator: %d", code)
+			}
+		}
+	}
+}