test(freeze): 增长冻结改盯耦合，行数降为粗护栏

Home() useState/useRef 与 JyotishAPIHandler 类方法/__new__ 不得增长。行数改为开工实测基线加余量。产品授权删除参数式 hook 零 React hook 规则。

frontend/tests/chart-view-route.test.ts

@@ -296,8 +296,9 @@ test("the golden chart-view envelope stays inside the page contract", () => {
   assert.match(COORDINATE_BOUNDARY.qizheng, /角宿/);
 });
 
-test("page.tsx does not grow to host the chart page", () => {
-  assert.ok((pageSource.match(/\n/g) ?? []).length <= 1951);
+test("page.tsx does not host the chart page", () => {
+  // Line-count freeze moved to tests/home-shell-growth-contract.test.ts
+  // (Home() useState / useRef caps + coarse line-count guardrail).
   assert.doesNotMatch(pageSource, /chart-page|ChartPageView|\/api\/chart-view/);
 });
 

frontend/tests/home-shell-growth-contract.test.ts

@@ -0,0 +1,53 @@
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import test from "node:test";
+
+const pageSource = readFileSync(new URL("../src/app/page.tsx", import.meta.url), "utf8");
+
+// Measured 2026-09-16 on origin/staging @ 51a65d92.
+// Line count: (pageSource.match(/\n/g) ?? []).length, same as `wc -l` = 1951.
+// Hook counts use \buseState[<(] / \buseRef[<(] so `useState<Type>(` is not missed.
+// Former line-count assertion lived in tests/chart-view-route.test.ts
+// (`page.tsx does not grow to host the chart page`).
+const PAGE_LINE_COUNT_BASELINE = 1951;
+const PAGE_LINE_COUNT_CAP = PAGE_LINE_COUNT_BASELINE + 150;
+const HOME_USE_STATE_CAP = 66;
+const HOME_USE_REF_CAP = 41;
+
+const USE_STATE_RE = /\buseState[<(]/g;
+const USE_REF_RE = /\buseRef[<(]/g;
+
+function homeSource(source: string): string {
+  const marker = "export default function Home(";
+  const start = source.indexOf(marker);
+  assert.notEqual(start, -1, "page.tsx must export default function Home(");
+  return source.slice(start);
+}
+
+function countMatches(source: string, pattern: RegExp): number {
+  return source.match(new RegExp(pattern.source, "g"))?.length ?? 0;
+}
+
+test("Home() useState count must not grow", () => {
+  const n = countMatches(homeSource(pageSource), USE_STATE_RE);
+  assert.ok(
+    n <= HOME_USE_STATE_CAP,
+    `Home() has ${n} useState calls; cap is ${HOME_USE_STATE_CAP}. Extracted hooks and child components should own their own state.`,
+  );
+});
+
+test("Home() useRef count must not grow", () => {
+  const n = countMatches(homeSource(pageSource), USE_REF_RE);
+  assert.ok(
+    n <= HOME_USE_REF_CAP,
+    `Home() has ${n} useRef calls; cap is ${HOME_USE_REF_CAP}. Do not rewrite state as refs to dodge the useState freeze.`,
+  );
+});
+
+test("page.tsx line count stays within the coarse guardrail", () => {
+  const n = (pageSource.match(/\n/g) ?? []).length;
+  assert.ok(
+    n <= PAGE_LINE_COUNT_CAP,
+    `page.tsx has ${n} lines; cap is ${PAGE_LINE_COUNT_CAP} (${PAGE_LINE_COUNT_BASELINE} baseline + 150).`,
+  );
+});