feat(admin): dashboard home, telemetry section, enrollment ops screen

- mission-control dashboard: now strip, tournament quick actions, usage
  sparklines, error feed, live activity, tools list
- /admin/telemetry with functions/events/errors/players/usage child routes,
  hand-rolled svg chart primitives, decomposed activities table
- error browser with grouping and mark-resolved
- consolidated per-tournament enrollment screen; hub simplified with
  run tournament promoted
- /admin/activities redirects to /admin/telemetry/functions

src/features/telemetry/components/charts/stat-tile.tsx

@@ -0,0 +1,53 @@
+import { ReactNode } from "react";
+import { Box, Card, Group, Stack, Text, UnstyledButton } from "@mantine/core";
+import Sparkline from "./sparkline";
+
+interface StatTileProps {
+  label: ReactNode;
+  value: ReactNode;
+  delta?: number;
+  spark?: number[];
+  caption?: ReactNode;
+  onClick?: () => void;
+}
+
+export const StatTile = ({ label, value, delta, spark, caption, onClick }: StatTileProps) => {
+  const content = (
+    <Stack gap={4}>
+      <Text size="xs" c="dimmed">
+        {label}
+      </Text>
+      <Group gap="xs" align="baseline" wrap="nowrap">
+        <Text fz={24} fw={600} lh={1.2}>
+          {value}
+        </Text>
+        {delta !== undefined && delta !== 0 && (
+          <Text size="xs" c={delta > 0 ? "green" : "red"}>
+            {delta > 0 ? "+" : ""}
+            {delta.toLocaleString()}
+          </Text>
+        )}
+      </Group>
+      {caption && <Box>{caption}</Box>}
+      {spark && spark.length > 0 && <Sparkline data={spark} height={28} />}
+    </Stack>
+  );
+
+  if (onClick) {
+    return (
+      <UnstyledButton onClick={onClick} w="100%">
+        <Card withBorder radius="md" p="md">
+          {content}
+        </Card>
+      </UnstyledButton>
+    );
+  }
+
+  return (
+    <Card withBorder radius="md" p="md">
+      {content}
+    </Card>
+  );
+};
+
+export default StatTile;