fix(site): use page count in usePaginatedQuery overshoot fallback (#30572)

Enables oxlint's `erasing-op` rule and fixes the one violation it found,
an operator precedence bug in `usePaginatedQuery`.

When the requested page reports a count of 0, the hook refetches page 1
to compute where to clamp. `Math.ceil(firstPageResult?.count ?? 0 /
limit)` parsed as `count ?? (0 / limit)`, so it used the record count as
the page count and left the user on the overshot page. The fix adds
parentheses, and a regression test covers it (the test fails without the
fix).

<details>
<summary>Context and findings</summary>

Part of evaluating oxlint's `correctness` category. Turning on the whole
category reported 1152 diagnostics across 24 rules, so rules are being
enabled one at a time instead, which keeps the explicit allowlist model
in `.oxlintrc.jsonc`. `erasing-op` had a single hit, and it was a real
bug.

Validation: `pnpm run lint` (Biome, oxlint, types, circular deps, React
Compiler, knip) and the full unit suite.

</details>

_Generated by Coder Agents on behalf of @jeremyruppel._

site/.oxlintrc.jsonc

@@ -109,6 +109,7 @@
 		"require-yield": "error",
 		"rules-of-hooks": "error",
 		"refs": "error",
+		"erasing-op": "error",
 
 		// --- security ---
 		"jsx-no-target-blank": "error",

site/src/hooks/usePaginatedQuery.test.ts

@@ -228,6 +228,21 @@ describe(usePaginatedQuery.name, () => {
 			await waitFor(() => expect(result.current.currentPage).toBe(1));
 		});
 
+		it("No custom callback: uses the first page's count when an overshot page reports a count of 0", async () => {
+			const mockQueryFn = vi.fn(({ pageNumber }: { pageNumber: number }) =>
+				Promise.resolve({ data: [], count: pageNumber === 1 ? 100 : 0 }),
+			);
+			const { result } = await render(
+				{
+					queryKey: ({ pageNumber }) => ["overshoot", pageNumber],
+					queryFn: mockQueryFn,
+				},
+				"/?page=35",
+			);
+
+			await waitFor(() => expect(result.current.currentPage).toBe(4));
+		});
+
 		it("With custom callback: Calls callback and does not update search params automatically", async () => {
 			const testControl = new URLSearchParams({
 				page: "1000",

site/src/hooks/usePaginatedQuery.ts

@@ -232,7 +232,7 @@ export function usePaginatedQuery<
 			const firstPageOptions = getQueryOptionsFromPage(1);
 			try {
 				const firstPageResult = await queryClient.fetchQuery(firstPageOptions);
-				const rounded = Math.ceil(firstPageResult?.count ?? 0 / limit);
+				const rounded = Math.ceil((firstPageResult?.count ?? 0) / limit);
 				fixedTotalPages = Math.max(rounded, 1);
 			} catch {
 				fixedTotalPages = 1;