把 404 頁接上未匹配的路徑

.gitignore

@@ -2,6 +2,9 @@
 dist/
 # generated types
 .astro/
+# `npx wrangler dev` 的本機狀態。本機不安裝 wrangler（見 wrangler.jsonc 開頭），
+# 但要親眼確認未匹配路徑真的拿得到 404 頁時，只有它跑得起 Workers 的資產路由。
+.wrangler/
 
 # 字體子集化的原始檔快取（scripts/subset-fonts.py 會自行下載）
 scripts/.fontcache/

README.md

@@ -79,6 +79,19 @@ Cloudflare 建置：`npm run build` → `npx wrangler deploy`。建置設定在
 - `wrangler.jsonc` 供 `npx wrangler deploy` 讀取，在 Cloudflare 的建置環境執行。
   本機不需要 wrangler，因此不在 dependencies，也沒有 `deploy` script。
 - 本站不落在任何節點上：不進 hoshi-deploy inventory，origin 憑證不含 `hoshivel.com`。
+- 未匹配的路徑由 `assets.not_found_handling` 交給 `dist/404.html`。這個鍵的預設值
+  `"none"` 回的是**零位元組**的 404——`src/pages/404.astro` 存在、`astro build`
+  也產得出 `dist/404.html`，兩者都不代表它被服務。要親眼確認就在本機跑一次
+  Workers 的資產路由（一次性，不加進 dependencies）：
+
+  ```sh
+  npx astro build
+  npx wrangler dev --port 26829
+  curl -sS -i http://127.0.0.1:26829/zzz-not-here
+  ```
+
+  要看到 `404` 後面**接著一份 HTML**。空白的 body 會被瀏覽器畫成白頁、分頁標題
+  退回原始 URL，看起來像整個站掛了，而不是路徑打錯。
 
 `hoshi build` 產生 `dist/` 靜態檔。**不得**加入 SSR adapter、server／hybrid
 output、Node runtime 或容器產物——部署的是純靜態資產。

test/not-found.test.mjs

@@ -0,0 +1,99 @@
+/*
+  The 404 page only exists if something serves it.
+
+  `src/pages/404.astro` was here from early on and `astro build` has always
+  written `dist/404.html`, yet every unmatched path on hoshivel.com returned a
+  404 with a ZERO-BYTE body until 2026-09-03. The gap was one key in
+  `wrangler.jsonc`: `assets.not_found_handling` defaults to `"none"`, which
+  answers unmatched requests with an empty response and never opens `404.html`.
+
+  A browser paints an empty body as a blank white page and falls back to the raw
+  URL for the tab title, so the failure looks like a crashed site rather than a
+  typo. The sister site sr-web had the identical defect and the identical fix;
+  see the workspace decision
+  `decisions/infrastructure/Workers-靜態站要顯式開啟-404-頁.md`.
+
+  Nothing in the build catches this: the page compiles, the asset is emitted, the
+  deploy succeeds. Only these assertions stand between the config and a silent
+  return to the blank page.
+*/
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import test from "node:test";
+
+import { ui as dictionaries } from "../src/i18n/ui.ts";
+
+const read = (path) => readFileSync(new URL(path, import.meta.url), "utf8");
+
+/**
+ * Strip JSONC comments without touching comment-like text inside strings, so a
+ * value such as an "https://" URL cannot truncate the parse.
+ */
+const parseJsonc = (source) => {
+  let out = "";
+  let inString = false;
+  let escaped = false;
+  for (let i = 0; i < source.length; i += 1) {
+    const ch = source[i];
+    if (inString) {
+      out += ch;
+      if (escaped) escaped = false;
+      else if (ch === "\\") escaped = true;
+      else if (ch === '"') inString = false;
+      continue;
+    }
+    if (ch === '"') {
+      inString = true;
+      out += ch;
+      continue;
+    }
+    if (ch === "/" && source[i + 1] === "/") {
+      while (i < source.length && source[i] !== "\n") i += 1;
+      out += "\n";
+      continue;
+    }
+    if (ch === "/" && source[i + 1] === "*") {
+      i += 2;
+      while (i < source.length && !(source[i] === "*" && source[i + 1] === "/")) i += 1;
+      i += 1;
+      continue;
+    }
+    out += ch;
+  }
+  return JSON.parse(out);
+};
+
+const wrangler = parseJsonc(read("../wrangler.jsonc"));
+const astroConfig = read("../astro.config.mjs");
+const page = read("../src/pages/404.astro");
+
+test("unmatched paths are answered with the 404 page, not an empty body", () => {
+  assert.equal(
+    wrangler.assets?.not_found_handling,
+    "404-page",
+    'assets.not_found_handling must be "404-page"; the default "none" returns a zero-byte 404',
+  );
+});
+
+test("the asset directory Workers serves is the one Astro builds into", () => {
+  // The 404 wiring is worth nothing if it points at a directory the build never
+  // fills. Astro's outDir is left at its default here, so `dist` is the contract
+  // between the two files — assert the config has not quietly moved.
+  assert.match(wrangler.assets?.directory ?? "", /^\.\/dist\/?$/);
+  assert.doesNotMatch(astroConfig, /outDir/, "astro outDir moved; wrangler assets.directory must follow");
+});
+
+test("the 404 page draws its copy from the shared dictionary", () => {
+  // Hardcoded strings here drift away from src/i18n/ui.ts on the next copy pass,
+  // and this page is the one nobody opens on purpose.
+  for (const key of ["notfound.title", "notfound.body", "notfound.back"]) {
+    assert.ok(page.includes(`"${key}"`), `404.astro must use ${key}`);
+    for (const [locale, dictionary] of Object.entries(dictionaries)) {
+      assert.ok(dictionary[key]?.trim(), `${locale}/${key} must not be empty`);
+    }
+  }
+});
+
+test("the 404 page links back into the site", () => {
+  assert.match(page, /href="\/"/, "404.astro must offer a link home");
+});

wrangler.jsonc

@@ -6,6 +6,12 @@
   "name": "hoshivel-web",
   "compatibility_date": "2026-08-10",
   "assets": {
-    "directory": "./dist"
+    "directory": "./dist",
+    // 未匹配的路徑要拿到 `dist/404.html`。這個鍵的預設值是 `"none"`，而 `"none"`
+    // 回的是一份**零位元組**的 404：瀏覽器把空 body 畫成白頁、分頁標題退回原始
+    // URL，看起來就像站掛了。`src/pages/404.astro` 在、`dist/404.html` 也一直
+    // 建置得出來，缺的只有這一行——三者單獨看都正常，症狀卻指向別處。
+    // 理由見 workspace 的 decisions/infrastructure/Workers-靜態站要顯式開啟-404-頁.md。
+    "not_found_handling": "404-page"
   }
 }