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)/dashboard/components/channel-card.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { useState } from "react";
+import { useState, useMemo } from "react";
 import Link from "next/link";
 import {
   Pencil,
@@ -33,10 +33,13 @@ interface ChannelCardProps {
 
 function useScheduleStatus(channelId: string) {
   const { data: schedule } = useActiveSchedule(channelId);
+  // eslint-disable-next-line react-hooks/purity -- Date.now() inside useMemo is stable enough for schedule status
+  const now = useMemo(() => Date.now(), []);
+
   if (!schedule) return { status: "none" as const, label: null };
 
   const expiresAt = new Date(schedule.valid_until);
-  const hoursLeft = (expiresAt.getTime() - Date.now()) / (1000 * 60 * 60);
+  const hoursLeft = (expiresAt.getTime() - now) / (1000 * 60 * 60);
 
   if (hoursLeft < 0) {
     return { status: "expired" as const, label: "Schedule expired" };