refactor: remove unused code and simplify implementations

Removes extensive dead code including unused components, utilities, and augmentations that were no longer referenced in the codebase.

Simplifies play settings logic by removing complex stream ranking algorithm in favor of direct previous index matching for audio and subtitle selections.

Removes aspectRatio prop from video player as it was set to a constant "default" value and never changed.

Inlines POSTER_CAROUSEL_HEIGHT constant directly where used instead of importing from centralized constants file.

Eliminates unused features including image color extraction for TV platforms, M3U8 subtitle parsing, and various Jellyfin API helpers that were no longer needed.

Cleans up credential management by making internal helper functions private that should not be exposed to external consumers.

components/posters/EpisodePoster.tsx

@@ -1,63 +0,0 @@
-import type { BaseItemDto } from "@jellyfin/sdk/lib/generated-client/models";
-import { Image } from "expo-image";
-import { useAtom } from "jotai";
-import { useMemo, useState } from "react";
-import { View } from "react-native";
-import { WatchedIndicator } from "@/components/WatchedIndicator";
-import { apiAtom } from "@/providers/JellyfinProvider";
-
-type MoviePosterProps = {
-  item: BaseItemDto;
-  showProgress?: boolean;
-};
-
-export const EpisodePoster: React.FC<MoviePosterProps> = ({
-  item,
-  showProgress = false,
-}) => {
-  const [api] = useAtom(apiAtom);
-
-  const url = useMemo(() => {
-    if (item.Type === "Episode") {
-      return `${api?.basePath}/Items/${item.ParentBackdropItemId}/Images/Thumb?fillHeight=389&quality=80&tag=${item.ParentThumbImageTag}`;
-    }
-  }, [item]);
-
-  const [progress, _setProgress] = useState(
-    item.UserData?.PlayedPercentage || 0,
-  );
-
-  const blurhash = useMemo(() => {
-    const key = item.ImageTags?.Primary as string;
-    return item.ImageBlurHashes?.Primary?.[key];
-  }, [item]);
-
-  return (
-    <View className='relative rounded-lg overflow-hidden border border-neutral-900'>
-      <Image
-        placeholder={{
-          blurhash,
-        }}
-        key={item.Id}
-        id={item.Id}
-        source={
-          url
-            ? {
-                uri: url,
-              }
-            : null
-        }
-        cachePolicy={"memory-disk"}
-        contentFit='cover'
-        style={{
-          aspectRatio: "10/15",
-          width: "100%",
-        }}
-      />
-      <WatchedIndicator item={item} />
-      {showProgress && progress > 0 && (
-        <View className='h-1 bg-red-600 w-full' />
-      )}
-    </View>
-  );
-};

components/posters/ParentPoster.tsx

@@ -1,48 +0,0 @@
-import { Image } from "expo-image";
-import { useAtom } from "jotai";
-import { useMemo } from "react";
-import { View } from "react-native";
-import { apiAtom } from "@/providers/JellyfinProvider";
-
-type PosterProps = {
-  id?: string;
-  showProgress?: boolean;
-};
-
-const ParentPoster: React.FC<PosterProps> = ({ id }) => {
-  const [api] = useAtom(apiAtom);
-
-  const url = useMemo(
-    () => `${api?.basePath}/Items/${id}/Images/Primary`,
-    [id],
-  );
-
-  if (!url || !id)
-    return (
-      <View
-        className='border border-neutral-900'
-        style={{
-          aspectRatio: "10/15",
-        }}
-      />
-    );
-
-  return (
-    <View className='rounded-lg overflow-hidden border border-neutral-900'>
-      <Image
-        key={id}
-        id={id}
-        source={{
-          uri: url,
-        }}
-        cachePolicy={"memory-disk"}
-        contentFit='cover'
-        style={{
-          aspectRatio: "10/15",
-        }}
-      />
-    </View>
-  );
-};
-
-export default ParentPoster;