refactor: split monolithic state into context-based modules

Extract image, desktop, mobile, and config state into separate context
providers to improve modularity and reduce unnecessary re-renders.

Signed-off-by: Sped0n <hi@sped0n.com>

assets/ts/imageState.tsx

@@ -0,0 +1,41 @@
+import {
+  createContext,
+  createMemo,
+  useContext,
+  type Accessor,
+  type JSX
+} from 'solid-js'
+import invariant from 'tiny-invariant'
+
+import type { ImageJSON } from './resources'
+
+export interface ImageState {
+  images: ImageJSON[]
+  length: number
+}
+
+type ImageStateContextType = Accessor<ImageState>
+
+const ImageStateContext = createContext<ImageStateContextType>()
+
+export function ImageStateProvider(props: {
+  children?: JSX.Element
+  images: ImageJSON[]
+}): JSX.Element {
+  const state = createMemo<ImageState>(() => ({
+    images: props.images,
+    length: props.images.length
+  }))
+
+  return (
+    <ImageStateContext.Provider value={state}>
+      {props.children}
+    </ImageStateContext.Provider>
+  )
+}
+
+export function useImageState(): ImageStateContextType {
+  const context = useContext(ImageStateContext)
+  invariant(context, 'undefined image context')
+  return context
+}