chore(frontend): update dependencies and adapt to oxlint 1.79

npm install was failing with ERESOLVE: the lockfile pinned storybook 10.5.7
and vitest 4.1.10 as peers while package.json asked for ^10.5.9 and ^4.1.11,
and npm would not move either. Neither npm update, a targeted install, nor
--package-lock-only broke the cycle, so node_modules and package-lock.json
were regenerated from scratch (601 packages, 0 vulnerabilities).

oxlint 1.79.0 then promoted five React Compiler rules into the correctness
category, flagging 101 pre-existing sites. 1.78.0 exits 0 on the same tree,
so nothing in our code changed - the rule set grew. They are fixed rather
than suppressed:

- refs (31): latest-value ref writes moved out of render into an effect.
  onlineClientsRef turned out to be write-only and is gone; expireDiffRef
  and trafficDiffRef were replaced by reading the values directly.
- set-state-in-effect (55): reset-on-open modals now adjust state during
  render; where an effect mixed a synchronous reset with an async fetch, the
  reset moved to render and the effect kept only the request. useMediaQuery
  became useSyncExternalStore.
- preserve-manual-memoization (11): optional-chained deps the compiler cannot
  match, hoisted to locals or dropped where the memo wrapped a string concat.
- purity (3): Date.now() in render replaced by a state-backed clock, which
  also refreshes the expiry tag every 60s instead of freezing it until the
  next unrelated re-render.
- immutability (1): applyClientStatsEvent merged websocket traffic into
  DBInbound rows in place; it now rebuilds only the rows it touches.

Two things fell out of that. clientCount is derived with useMemo instead of
an imperative rebuildClientCount() called from five sites, which also fixes a
staleness bug where changing the expiry or traffic threshold left the counts
alone until some later rebuild. statsVersion existed only to force a
re-render after an in-place mutation, is meaningless now that rows are
replaced, and nothing read it, so it is removed.

Also adds a lint:fix script - oxlint --fix was previously only reachable
through the lint-staged hook.

frontend/src/hooks/useMediaQuery.ts

@@ -1,4 +1,4 @@
-import { useEffect, useState } from 'react';
+import { useCallback, useSyncExternalStore } from 'react';
 
 export const MOBILE_BREAKPOINT_PX = 768;
 
@@ -11,17 +11,21 @@ export const MOBILE_BREAKPOINT_PX = 768;
  */
 export function useMediaQuery(breakpoint: number = MOBILE_BREAKPOINT_PX) {
   const query = `(max-width: ${breakpoint}px)`;
-  const [isMobile, setIsMobile] = useState<boolean>(() =>
-    typeof window !== 'undefined' ? window.matchMedia(query).matches : false,
+
+  const subscribe = useCallback(
+    (onStoreChange: () => void) => {
+      const mql = window.matchMedia(query);
+      mql.addEventListener('change', onStoreChange);
+      return () => mql.removeEventListener('change', onStoreChange);
+    },
+    [query],
   );
 
-  useEffect(() => {
-    const mql = window.matchMedia(query);
-    const onChange = (e: MediaQueryListEvent) => setIsMobile(e.matches);
-    mql.addEventListener('change', onChange);
-    setIsMobile(mql.matches);
-    return () => mql.removeEventListener('change', onChange);
-  }, [query]);
+  const isMobile = useSyncExternalStore(
+    subscribe,
+    () => window.matchMedia(query).matches,
+    () => false,
+  );
 
   return { isMobile };
 }