feat(guide): implement channel guide page with EPG and upcoming slots

feat(layout): add guide link to navigation
feat(tv): enable channel navigation via query parameter

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

@@ -1,6 +1,7 @@
 "use client";
 
 import { useState, useEffect, useCallback, useRef } from "react";
+import { useSearchParams } from "next/navigation";
 import { useQueryClient } from "@tanstack/react-query";
 import {
   VideoPlayer,
@@ -37,12 +38,19 @@ const BANNER_THRESHOLD = 80; // show "up next" when progress ≥ this %
 
 export default function TvPage() {
   const { token } = useAuthContext();
+  const searchParams = useSearchParams();
 
   // Channel list
   const { data: channels, isLoading: isLoadingChannels } = useChannels();
 
-  // Channel navigation
+  // Channel navigation — seed from ?channel=<id> query param if present
   const [channelIdx, setChannelIdx] = useState(0);
+  useEffect(() => {
+    const id = searchParams.get("channel");
+    if (!id || !channels) return;
+    const idx = channels.findIndex((c) => c.id === id);
+    if (idx !== -1) setChannelIdx(idx);
+  }, [channels, searchParams]);
   const channel = channels?.[channelIdx];
 
   // Overlay / idle state