refactor: extract magic constants — wave 2 (TanStack Query defaults)

Promote the duplicated query lifecycle constants in \$shared/api/queryClient.ts:

- staleTime (5 minutes) -> DEFAULT_QUERY_STALE_TIME_MS
- gcTime (10 minutes)   -> DEFAULT_QUERY_GC_TIME_MS
- retry (3)             -> QUERY_RETRY_COUNT
- retryDelay (1s base, 30s cap) -> QUERY_RETRY_BASE_DELAY_MS + QUERY_RETRY_MAX_DELAY_MS

fontCatalogStore and availableFilterStore now import the stale/gc
constants instead of re-deriving '5 * 60 * 1000' / '10 * 60 * 1000'.

fontCatalogStore.svelte.spec.ts's queryClient mock now passes through
the new named exports via importOriginal so the consumer's imports
resolve.

src/entities/Font/model/store/fontCatalogStore/fontCatalogStore.svelte.spec.ts

@@ -19,11 +19,15 @@ import {
 import type { UnifiedFont } from '../../types';
 import { FontCatalogStore } from './fontCatalogStore.svelte';
 
-vi.mock('$shared/api/queryClient', () => ({
+vi.mock('$shared/api/queryClient', async importOriginal => {
+    const actual = await importOriginal<typeof import('$shared/api/queryClient')>();
+    return {
+        ...actual,
         queryClient: new QueryClient({
             defaultOptions: { queries: { retry: 0, gcTime: 0 } },
         }),
-}));
+    };
+});
 vi.mock('../../../api', () => ({ fetchProxyFonts: vi.fn() }));
 
 import { queryClient } from '$shared/api/queryClient';

src/entities/Font/model/store/fontCatalogStore/fontCatalogStore.svelte.ts

@@ -1,4 +1,8 @@
-import { queryClient } from '$shared/api/queryClient';
+import {
+    DEFAULT_QUERY_GC_TIME_MS,
+    DEFAULT_QUERY_STALE_TIME_MS,
+    queryClient,
+} from '$shared/api/queryClient';
 import {
     type InfiniteData,
     InfiniteQueryObserver,
@@ -427,8 +431,8 @@ export class FontCatalogStore {
                 const next = lastPage.offset + lastPage.limit;
                 return next < lastPage.total ? { offset: next } : undefined;
             },
-            staleTime: hasFilters ? 0 : 5 * 60 * 1000,
+            staleTime: hasFilters ? 0 : DEFAULT_QUERY_STALE_TIME_MS,
-            gcTime: 10 * 60 * 1000,
+            gcTime: DEFAULT_QUERY_GC_TIME_MS,
         };
     }
 

src/features/FilterAndSortFonts/model/store/availableFilterStore/availableFilterStore.svelte.ts

@@ -17,7 +17,11 @@
 
 import { fetchProxyFilters } from '$features/FilterAndSortFonts/api/filters/filters';
 import type { FilterMetadata } from '$features/FilterAndSortFonts/api/filters/filters';
-import { queryClient } from '$shared/api/queryClient';
+import {
+    DEFAULT_QUERY_GC_TIME_MS,
+    DEFAULT_QUERY_STALE_TIME_MS,
+    queryClient,
+} from '$shared/api/queryClient';
 import {
     type QueryKey,
     QueryObserver,
@@ -81,8 +85,8 @@ export class AvailableFilterStore {
         return {
             queryKey: this.getQueryKey(),
             queryFn: () => this.fetchFn(),
-            staleTime: 5 * 60 * 1000, // 5 minutes
+            staleTime: DEFAULT_QUERY_STALE_TIME_MS,
-            gcTime: 10 * 60 * 1000, // 10 minutes
+            gcTime: DEFAULT_QUERY_GC_TIME_MS,
         };
     }
 

src/shared/api/queryClient.ts

@@ -1,5 +1,31 @@
 import { QueryClient } from '@tanstack/query-core';
 
+/**
+ * Data remains fresh for this long after fetch. Stores that override
+ * staleness (e.g. filtered queries) can use 0 to bypass.
+ */
+export const DEFAULT_QUERY_STALE_TIME_MS = 5 * 60 * 1000;
+
+/**
+ * Unused cache entries are garbage collected after this long.
+ */
+export const DEFAULT_QUERY_GC_TIME_MS = 10 * 60 * 1000;
+
+/**
+ * How many times a failed query is retried before surfacing the error.
+ */
+export const QUERY_RETRY_COUNT = 3;
+
+/**
+ * Base delay for exponential retry backoff.
+ */
+export const QUERY_RETRY_BASE_DELAY_MS = 1000;
+
+/**
+ * Upper bound on retry delay regardless of attempt index.
+ */
+export const QUERY_RETRY_MAX_DELAY_MS = 30000;
+
 /**
  * TanStack Query client instance
  *
@@ -15,14 +41,8 @@ import { QueryClient } from '@tanstack/query-core';
 export const queryClient = new QueryClient({
     defaultOptions: {
         queries: {
-            /**
+            staleTime: DEFAULT_QUERY_STALE_TIME_MS,
-             * Data remains fresh for 5 minutes after fetch
+            gcTime: DEFAULT_QUERY_GC_TIME_MS,
-             */
-            staleTime: 5 * 60 * 1000,
-            /**
-             * Unused cache entries are removed after 10 minutes
-             */
-            gcTime: 10 * 60 * 1000,
             /**
              * Don't refetch when window regains focus
              */
@@ -31,15 +51,12 @@ export const queryClient = new QueryClient({
              * Refetch on mount if data is stale
              */
             refetchOnMount: true,
+            retry: QUERY_RETRY_COUNT,
             /**
-             * Retry failed requests up to 3 times
+             * Exponential backoff: 1s, 2s, 4s, 8s... capped at 30s
              */
-            retry: 3,
+            retryDelay: attemptIndex =>
-            /**
+                Math.min(QUERY_RETRY_BASE_DELAY_MS * 2 ** attemptIndex, QUERY_RETRY_MAX_DELAY_MS),
-             * Exponential backoff for retries
-             * 1s, 2s, 4s, 8s... capped at 30s
-             */
-            retryDelay: attemptIndex => Math.min(1000 * 2 ** attemptIndex, 30000),
         },
     },
 });