refactor: simplify request handlers and deduplicate config

- Re-enable TanStack Query retry (retry: 3 with exponential backoff),
  delete all server-side retry logic from request handlers
- Strip handler factories to bare minimum: remove isValid, retry, widgetKind
- Remove redundant refetchOnWindowFocus/refetchOnReconnect from docker-table
- Deduplicate queryCacheMaxValueBytes (pass as param, single source of truth)
- Simplify system-resources chart: use dataUpdatedAt instead of ref-based tracking
- Fix leading blank lines in 27 request handler files

packages/api/src/router/query-cache.ts

@@ -25,7 +25,7 @@ export const queryCacheRouter = createTRPCRouter({
     await validateBoardAccessAsync(ctx, input.boardId);
     const userId = ctx.session?.user.id ?? "anonymous";
     return {
-      stored: await setQueryCacheAsync(userId, input.boardId, input.value, queryCacheDefaultGcTimeMs),
+      stored: await setQueryCacheAsync(userId, input.boardId, input.value, queryCacheDefaultGcTimeMs, queryCacheMaxValueBytes),
     };
   }),
   removeItem: publicProcedure.input(queryCacheBoardInput).mutation(async ({ ctx, input }) => {

packages/api/src/test/query-cache.spec.ts

@@ -19,8 +19,8 @@ const redisMock = vi.hoisted(() => {
 
   return {
     values,
-    setQueryCacheAsync: vi.fn(async (_userId: string, _boardId: string, value: string, _ttlMs: number) => {
-      if (Buffer.byteLength(value, "utf8") > 1024 * 1024) return false;
+    setQueryCacheAsync: vi.fn(async (_userId: string, _boardId: string, value: string, _ttlMs: number, maxValueBytes: number) => {
+      if (Buffer.byteLength(value, "utf8") > maxValueBytes) return false;
       values.set(`${_userId}:${_boardId}`, value);
       return true;
     }),