feat: implement smart watchlist refresh on navigation

Added intelligent watchlist refresh mechanism that only refetches data when changes are actually made, preventing unnecessary API calls and improving performance.

Changes:
- Added watchlistNeedsRefresh store to track when watchlist data has changed
- Implemented reactive watcher in App.svelte that uses svelte-spa-router's loc store to detect navigation to home
- Set dirty flag in Anime.svelte after successful status updates and entry deletions
- Added conditional refresh logic that checks user's primary service (AniList, MAL, or Simkl)
- Parallel refresh support for multiple services when logged in

This resolves the issue where clicking the logo would cause full page reloads and unnecessary re-authentication checks, while also ensuring watchlist data stays current when users make changes.

Technical details:
- Uses $loc.location to detect route changes
- IIFE pattern for async operations in reactive statements
- Only refreshes for logged-in primary services
- Flag resets after successful refresh

Related to: Header.svelte client-side routing fix

frontend/src/App.svelte

@@ -1,42 +1,69 @@
 <script lang="ts">
-    import {
-        aniListLoggedIn,
-        malLoggedIn,
-        simklLoggedIn,
-    } from "./helperModules/GlobalVariablesAndHelperFunctions.svelte";
-    import {onMount} from "svelte";
-    import Router from "svelte-spa-router"
-    import Home from "./routes/Home.svelte";
-    import {wrap} from "svelte-spa-router/wrap";
-    import Spinner from "./helperComponents/Spinner.svelte";
-    import Header from "./helperComponents/Header.svelte";
-    import {CheckIfAniListLoggedInAndLoadWatchList} from "./helperModules/CheckIfAniListLoggedInAndLoadWatchList.svelte";
-    import { CheckIfMALLoggedInAndSetUser } from "./helperModules/CheckIfMyAnimeListLoggedIn.svelte";
-    import {CheckIfSimklLoggedInAndSetUser} from "./helperModules/CheckIsSimklLoggedIn.svelte"
-    import {CheckIfAniListLoggedIn} from "../wailsjs/go/main/App";
+  import {
+    aniListLoggedIn,
+    malLoggedIn,
+    simklLoggedIn,
+    watchlistNeedsRefresh,
+    aniListPrimary,
+    malPrimary,
+    simklPrimary,
+    malWatchList,
+    simklWatchList,
+  } from "./helperModules/GlobalVariablesAndHelperFunctions.svelte";
+  import { onMount } from "svelte";
+  import Router from "svelte-spa-router";
+  import Home from "./routes/Home.svelte";
+  import { wrap } from "svelte-spa-router/wrap";
+  import Spinner from "./helperComponents/Spinner.svelte";
+  import Header from "./helperComponents/Header.svelte";
+  import { CheckIfAniListLoggedInAndLoadWatchList } from "./helperModules/CheckIfAniListLoggedInAndLoadWatchList.svelte";
+  import { CheckIfMALLoggedInAndSetUser } from "./helperModules/CheckIfMyAnimeListLoggedIn.svelte";
+  import { CheckIfSimklLoggedInAndSetUser } from "./helperModules/CheckIsSimklLoggedIn.svelte";
+  import {
+    CheckIfAniListLoggedIn,
+    GetMyAnimeList,
+    SimklGetUserWatchlist,
+  } from "../wailsjs/go/main/App";
+  import { loc } from "svelte-spa-router";  onMount(async () => {
+  onMount(async () => {
+    let isAniListLoggedIn: boolean;
+    let isMALLoggedIn: boolean;
+    let isSimklLoggedIn: boolean;
+    aniListLoggedIn.subscribe((value) => (isAniListLoggedIn = value));
+    malLoggedIn.subscribe((value) => (isMALLoggedIn = value));
+    simklLoggedIn.subscribe((value) => (isSimklLoggedIn = value));
 
-    onMount(async () => {
-        let isAniListLoggedIn: boolean
-        let isMALLoggedIn: boolean
-        let isSimklLoggedIn: boolean
-        aniListLoggedIn.subscribe((value) => isAniListLoggedIn = value)
-        malLoggedIn.subscribe((value) => isMALLoggedIn = value)
-        simklLoggedIn.subscribe((value) => isSimklLoggedIn = value)
+    !isAniListLoggedIn && (await CheckIfAniListLoggedInAndLoadWatchList());
+    !isMALLoggedIn && (await CheckIfMALLoggedInAndSetUser());
+    !isSimklLoggedIn && (await CheckIfSimklLoggedInAndSetUser());
+  });
 
-        console.log(isAniListLoggedIn)
-        !isAniListLoggedIn && await CheckIfAniListLoggedInAndLoadWatchList()
-        !isMALLoggedIn && await CheckIfMALLoggedInAndSetUser()
-        !isSimklLoggedIn && await CheckIfSimklLoggedInAndSetUser()
-    })
+  $: if ($loc?.location === "/" && $watchlistNeedsRefresh) {
+    (async () => {
+      if ($aniListLoggedIn && $aniListPrimary) {
+        await CheckIfAniListLoggedInAndLoadWatchList();
+      }
+      if ($malLoggedIn && $malPrimary) {
+        await GetMyAnimeList(1000).then((w) => malWatchList.set(w));
+      }
+      if ($simklLoggedIn && $simklPrimary) {
+        await SimklGetUserWatchlist().then((w) => simklWatchList.set(w));
+      }
+
+      watchlistNeedsRefresh.set(false);
+    })();
+  }
 </script>
 
 <Header />
-<Router routes={{
-    '/': Home,
-    '/anime/:id': wrap({
-        asyncComponent: () => import('./routes/AnimeRoutePage.svelte'),
-        conditions: [async () => await CheckIfAniListLoggedIn()],
-        loadingComponent: Spinner
+<Router
+  routes={{
+    "/": Home,
+    "/anime/:id": wrap({
+      asyncComponent: () => import("./routes/AnimeRoutePage.svelte"),
+      conditions: [async () => await CheckIfAniListLoggedIn()],
+      loadingComponent: Spinner,
     }),
     // '*': "Not Found"
-}} />
+  }}
+/>