feat(dictionary): add Hachidori backend support

- Add backend selection, setup gating, Anki integration, and external host support
- Add launcher flags, documentation, packaging, and focused tests
- Open on-demand overlay modals on the first attempt

vendor/hachidori/scripts/lint-firefox.mjs

@@ -0,0 +1,47 @@
+#!/usr/bin/env node
+// Lint the prepared Firefox extension with the pinned web-ext.
+// scripts/package-store.py builds the release XPI from the same file list.
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+import { readFile } from "node:fs/promises";
+import { spawnSync } from "node:child_process";
+import { dirname, resolve } from "node:path";
+import { fileURLToPath, pathToFileURL } from "node:url";
+
+import {
+  DEFAULT_FIREFOX_EXTENSION,
+  prepareFirefoxExtension,
+} from "./prepare-firefox.mjs";
+
+const ROOT = resolve(dirname(fileURLToPath(import.meta.url)), "..");
+const TOOLING = resolve(ROOT, "test/tooling");
+
+async function webExtBin() {
+  const packagePath = resolve(TOOLING, "node_modules/web-ext/package.json");
+  const packageJson = JSON.parse(await readFile(packagePath, "utf8"));
+  const entry = typeof packageJson.bin === "string" ? packageJson.bin : packageJson.bin?.["web-ext"];
+  if (typeof entry !== "string") throw new Error("The pinned web-ext executable is unavailable. Run npm ci --prefix test/tooling.");
+  return resolve(dirname(packagePath), entry);
+}
+
+export async function lintFirefoxExtension(output = DEFAULT_FIREFOX_EXTENSION) {
+  const source = await prepareFirefoxExtension(output);
+  const result = spawnSync(process.execPath, [await webExtBin(), "lint", "--source-dir", source], {
+    cwd: ROOT,
+    encoding: "utf8",
+    stdio: "inherit",
+  });
+  if (result.error) throw result.error;
+  if (result.status !== 0) throw new Error(`web-ext lint exited with status ${result.status}`);
+  return source;
+}
+
+if (process.argv[1] && import.meta.url === pathToFileURL(resolve(process.argv[1])).href) {
+  try {
+    if (process.argv.length > 2) throw new Error("usage: node scripts/lint-firefox.mjs");
+    await lintFirefoxExtension();
+  } catch (error) {
+    console.error(error instanceof Error ? error.message : String(error));
+    process.exitCode = 1;
+  }
+}