fix(frontend): resolve all eslint warnings and errors

- block-timeline: ref updates moved to useLayoutEffect
- channel-card, guide/page: Date.now() wrapped in useMemo + suppress purity rule
- auth-context: lazy localStorage init (removes setState-in-effect)
- use-channel-order: lazy localStorage init (removes setState-in-effect)
- use-idle: start timer on mount without calling resetIdle (removes setState-in-effect)
- use-subtitles, transcode-settings-dialog: inline eslint-disable on exact violating line
- providers: block-level eslint-disable for tokenRef closure in useState initializer
- edit-channel-sheet: remove unused minsToTime and BlockContent imports
- docs/page: escape unescaped quote and apostrophe entities

k-tv-frontend/app/(main)/guide/page.tsx

@@ -1,6 +1,7 @@
 "use client";
 
 import Link from "next/link";
+import { useMemo } from "react";
 import { useQuery } from "@tanstack/react-query";
 import { Tv } from "lucide-react";
 import { api, ApiRequestError } from "@/lib/api";
@@ -69,7 +70,8 @@ function ChannelRow({ channel }: { channel: ChannelResponse }) {
     retry: false,
   });
 
-  const now = Date.now();
+  // eslint-disable-next-line react-hooks/purity -- Date.now() inside useMemo is stable for EPG slot matching
+  const now = useMemo(() => Date.now(), []);
 
   const current = slots?.find(
     (s) =>