Chore: Port over Settings (Barely Works)

src/lib/state/app.svelte.ts

@@ -1,11 +1,46 @@
+export type NavPage =
+  | 'home' | 'library' | 'sources' | 'explore'
+  | 'downloads' | 'extensions' | 'history' | 'search' | 'tracking'
+
 export type AppStatus = 'booting' | 'not-configured' | 'auth' | 'ready' | 'error'
 
+class AppStore {
+  navPage:       NavPage = $state('home')
+  settingsOpen:  boolean = $state(false)
+  searchPrefill: string  = $state('')
+  searchQuery:   string  = $state('')
+  genreFilter:   string  = $state('')
+  scrollPositions: Map<string, number> = $state(new Map())
+
+  setNavPage(next: NavPage)        { this.navPage       = next }
+  setSettingsOpen(next: boolean)   { this.settingsOpen  = next }
+  setSearchPrefill(next: string)   { this.searchPrefill = next }
+  setSearchQuery(next: string)     { this.searchQuery   = next }
+  setGenreFilter(next: string)     { this.genreFilter   = next }
+  saveScroll(key: string, top: number) {
+    const m = new Map(this.scrollPositions)
+    m.set(key, top)
+    this.scrollPositions = m
+  }
+  getScroll(key: string): number { return this.scrollPositions.get(key) ?? 0 }
+}
+
+export const app = new AppStore()
+
 export const appState = $state({
-  status:          'booting' as AppStatus,
-  error:           null as string | null,
-  serverUrl:       '',
-  authenticated:   false,
-  authMode:        'NONE' as 'NONE' | 'BASIC_AUTH' | 'UI_LOGIN',
-  platform:        'web' as 'web' | 'tauri' | 'capacitor',
-  version:         '',
-})
+  status:        'booting' as AppStatus,
+  error:         null as string | null,
+  serverUrl:     '',
+  authenticated: false,
+  authMode:      'NONE' as 'NONE' | 'BASIC_AUTH' | 'UI_LOGIN',
+  platform:      'web' as 'web' | 'tauri' | 'capacitor',
+  version:       '',
+})
+
+export function setNavPage(next: NavPage)            { app.setNavPage(next) }
+export function setSettingsOpen(next: boolean)       { app.setSettingsOpen(next) }
+export function setSearchPrefill(next: string)       { app.setSearchPrefill(next) }
+export function setSearchQuery(next: string)         { app.setSearchQuery(next) }
+export function setGenreFilter(next: string)         { app.setGenreFilter(next) }
+export function saveScroll(key: string, top: number) { app.saveScroll(key, top) }
+export function getScroll(key: string): number       { return app.getScroll(key) }