perf(jobs): avoid locale-only application refetch

docs/i18n/CURRENT_STATUS.md

@@ -1,5 +1,7 @@
 # Current localisation continuation
 
+Changing the Jobs or Trash display language keeps the existing query results and localises the current error notice. See [the validated request-count comparison](JOBS_LOCALE_READS.md).
+
 Admin System database sizes and CV benchmark percentages now follow the EN/NB UI locale on the isolated admin-metrics branch. See [implementation and validation](ADMIN_METRIC_FORMATTING.md).
 
 Mobile application cards now use the selected EN/NB locale and existing salary-period labels on the isolated mobile-salary branch. See [the bounded implementation and validation](MOBILE_SALARY_FORMATTING.md). Full I18N-02 surface coverage and European locale acceptance remain open.

docs/i18n/JOBS_LOCALE_READS.md

@@ -0,0 +1,19 @@
+# Locale-only Jobs and Trash reads
+
+Bounded PERF-08/PERF-13 and I18N-02 work on `codex/perf-jobs-locale-read`, based on `4c12f7691ff5e73f537135ffed60c0b599c7ce37`. The same Jobs read dependency on translated text was present in the inspected A3 branch.
+
+Changing the UI language used to reload the same application-list query. The resource loader now tracks data inputs only. The existing error notice renders the current-language title and retains available server details. The shared resource and session hooks, query parameters, retry, data refresh and mutation paths remain intact. This change applies to Jobs and Trash. It does not affect saved language preference writes.
+
+The three focused assertions reproduced the redundant request before the fix. Afterwards 34 tests passed across JobTable, Offer Comparison, Jobs view and the I18n provider. The tests cover already-loaded mobile salaries and current Jobs and Trash errors switching to Bokmål, followed by an explicit retry of the same query. Full frontend typecheck, scoped ESLint with zero warnings and the Next static export passed.
+
+## Isolated browser measurement
+
+Chromium 151.0.7922.34, 1366 × 900, fresh browser context per route, local Next 16.4.1/Turbopack static export, no throttle. Loopback serving disables HTTP caching. Requests to external hosts were blocked. Route interception supplied synthetic API responses, including 15 synthetic application rows and a fixture session. Resource Timing identified loaded JavaScript and CSS. The table reports file byte sizes and offline gzip-6 estimates, excluding HTTP headers and runtime-generated styles.
+
+| Route | JS files before → after | Raw JS bytes before → after | Estimated gzip-6 JS bytes before → after |
+| --- | ---: | ---: | ---: |
+| Landing | 18 → 18 | 2,005,036 → 2,005,009 | 591,192 → 591,190 |
+| Login | 18 → 18 | 2,005,036 → 2,005,009 | 591,192 → 591,190 |
+| Jobs | 20 → 20 | 2,033,779 → 2,033,752 | 601,065 → 601,063 |
+
+All three routes reached their content marker and reported no page errors in both runs. Each loaded one 293-byte CSS file. Jobs made one initial paginated GET in both runs. After switching from English to Bokmål via the storage event, the paginated GET count changed from **one extra request to zero**. The initial Jobs fetch, authentication and other startup requests still occurred. Timing samples were single unthrottled loopback observations, so this checkpoint claims no latency or Web Vitals improvement. Native device, A3 integration and release qualification remain open.

job-tracker-ui/src/components/JobTable.tsx

@@ -316,8 +316,8 @@ export default function JobTable({ refreshToken, pageSize, onPageSizeChange, col
     {
       initialData: { items: [], total: 0, page: 1, pageSize },
       enabled: !boardView,
-      errorMessage: t("jobTableJobsLoadFailed"),
-      deps: [params, refreshToken, reloadToken, pageSize, t],
+      errorMessage: "", // ViewStateNotice renders the fallback in the current language.
+      deps: [params, refreshToken, reloadToken, pageSize],
     },
   );
 

job-tracker-ui/src/job-table-density.test.tsx

@@ -170,11 +170,13 @@ test("mobile salary follows UI language and preserves imported periods and free
     const card = (title: string) => screen.getByRole("link", { name: new RegExp(title, "i") });
     expect(normalize(card(job.jobTitle).textContent)).toContain(salary("en", translations.en.salaryPeriodYear));
     const params = lastParams();
+    const readCount = calls().length;
     await act(async () => { window.dispatchEvent(new StorageEvent("storage", { key: "uiLanguage", newValue: "nb" })); });
     expect(normalize(card(job.jobTitle).textContent)).toContain(salary("nb-NO", translations.nb.salaryPeriodYear));
     expect(within(card("Second role")).getByText("0/constructor")).toBeVisible();
     expect(within(card("Third role")).getByText("Lønn etter avtale")).toBeVisible();
     expect(lastParams()).toEqual(params);
+    expect(calls()).toHaveLength(readCount);
     expect(mockedApi.put).not.toHaveBeenCalled();
   } finally {
     if (previous) Object.defineProperty(window, "matchMedia", previous);
@@ -182,6 +184,28 @@ test("mobile salary follows UI language and preserves imported periods and free
   }
 });
 
+test.each(["jobs", "trash"] as const)("language changes localize the current %s read error without a new request", async (mode) => {
+  const title = mode === "jobs" ? "jobTableJobsLoadFailed" : "jobTableTrashLoadFailed";
+  mockedApi.get.mockImplementation((url: string) => url === "/jobapplications"
+    ? Promise.reject({ response: { status: 503 } })
+    : Promise.resolve({ data: [job.company] } as any));
+  show(mode, "?q=platform");
+  expect(await screen.findByRole("alert")).toHaveTextContent(translations.en[title]);
+  const readCount = calls().length;
+  const params = lastParams();
+  await act(async () => { window.dispatchEvent(new StorageEvent("storage", { key: "uiLanguage", newValue: "nb" })); });
+  expect(screen.getByRole("alert")).toHaveTextContent(translations.nb[title]);
+  expect(screen.queryByText(translations.en[title])).not.toBeInTheDocument();
+  expect(calls()).toHaveLength(readCount);
+  expect(mockedApi.put).not.toHaveBeenCalled();
+
+  mockedApi.get.mockResolvedValue({ data: { items: [], total: 0, page: 1, pageSize: 15 } } as any);
+  fireEvent.click(screen.getByRole("button", { name: translations.nb.retry }));
+  await waitFor(() => expect(screen.queryByRole("alert")).not.toBeInTheDocument());
+  expect(calls()).toHaveLength(readCount + 1);
+  expect(lastParams()).toEqual(params);
+});
+
 test("partial bulk failure refreshes successful rows and retains only failed visible IDs", async () => {
   const other = { ...job, id: 43, jobTitle: "Second role" };
   mockedApi.get.mockImplementation((url: string) => Promise.resolve({ data: url === "/companies" ? [job.company] : url === "/jobapplications" ? { items: [job, other], total: 2, page: 1, pageSize: 15 } : [] } as any));