refactor(admin): align admin ui with app design language

- dashboard: card grid replaced by status strip + nav-tile section + list
- nav-tile promoted to shared component
- stat tiles and usage screen de-carded, sections divided like settings
- hub run tournament back to a list row
- telemetry link restored in tools list

src/components/nav-tile/index.tsx

@@ -0,0 +1,28 @@
+import { Text, UnstyledButton } from "@mantine/core";
+import { Icon } from "@phosphor-icons/react";
+import classes from "./nav-tile.module.css";
+
+interface NavTileProps {
+  label: string;
+  Icon: Icon;
+  onClick?: () => void;
+  disabled?: boolean;
+}
+
+/** A single square-ish nav tile with icon-over-label and press feedback. */
+export const NavTile = ({ label, Icon, onClick, disabled }: NavTileProps) => (
+  <UnstyledButton
+    className={`${classes.tile} flxn-tile`}
+    onClick={onClick}
+    disabled={disabled}
+  >
+    <span className={`${classes.icon} flxn-tile-icon`}>
+      <Icon size={22} weight="bold" />
+    </span>
+    <Text size="xs" fw={600} lineClamp={2} lh={1.2}>
+      {label}
+    </Text>
+  </UnstyledButton>
+);
+
+export default NavTile;

src/components/nav-tile/nav-tile.module.css

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+.tile {
+    -webkit-tap-highlight-color: transparent;
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    gap: 8px;
+    padding: 14px 8px;
+    border-radius: var(--mantine-radius-md);
+    border: 1px solid var(--mantine-color-default-border);
+    background-color: var(--mantine-color-body);
+    text-align: center;
+}
+
+.icon {
+    color: var(--mantine-primary-color-filled);
+    display: flex;
+}
+
+@media (hover: hover) {
+    .tile:hover:not(:disabled) {
+        background-color: var(--mantine-color-default-hover);
+    }
+}
+
+.tile:active:not(:disabled) {
+    background-color: var(--mantine-color-default-hover);
+}
+
+.tile:disabled {
+    opacity: 0.5;
+    cursor: default;
+}
+
+@media (prefers-reduced-motion: no-preference) {
+    .tile {
+        transition: background-color 120ms ease-out, transform 120ms cubic-bezier(0.32, 0.72, 0, 1);
+    }
+
+    .tile:active:not(:disabled) {
+        transform: scale(0.97);
+    }
+}