tools: add sync-version.js to sync package.json -> Tauri files

- Add tools/sync-version.js script to read root package.json version
  and update src-tauri/tauri.conf.json and src-tauri/Cargo.toml.
- Update only the [package] version line in Cargo.toml to preserve formatting.
- Include JSON read/write helpers and basic error handling/reporting.

tools/sync-version.js

@@ -0,0 +1,60 @@
+#!/usr/bin/env node
+import fs from 'fs';
+import path from 'path';
+
+const repoRoot = process.cwd();
+
+function readJson(p) {
+  return JSON.parse(fs.readFileSync(p, 'utf8'));
+}
+
+function writeJson(p, obj) {
+  fs.writeFileSync(p, JSON.stringify(obj, null, 2) + '\n', 'utf8');
+}
+
+function updateCargoTomlVersion(cargoTomlPath, version) {
+  const input = fs.readFileSync(cargoTomlPath, 'utf8');
+
+  // Replace only the [package] version line.
+  const packageBlockStart = input.indexOf('[package]');
+  if (packageBlockStart === -1) {
+    throw new Error('Could not find [package] in Cargo.toml');
+  }
+
+  const packageBlockEnd = input.indexOf('\n[', packageBlockStart + 1);
+  const blockEnd = packageBlockEnd === -1 ? input.length : packageBlockEnd;
+  const pkgBlock = input.slice(packageBlockStart, blockEnd);
+
+  const versionRe = /^version\s*=\s*"([^"]*)"/m;
+  const m = pkgBlock.match(versionRe);
+  if (!m) {
+    throw new Error('Could not find version line in Cargo.toml [package] block');
+  }
+
+  const replaced = pkgBlock.replace(versionRe, `version = "${version}"`);
+
+  const output = input.slice(0, packageBlockStart) + replaced + input.slice(blockEnd);
+  fs.writeFileSync(cargoTomlPath, output, 'utf8');
+}
+
+try {
+  const rootPkgPath = path.join(repoRoot, 'package.json');
+  const tauriConfPath = path.join(repoRoot, 'src-tauri', 'tauri.conf.json');
+  const cargoTomlPath = path.join(repoRoot, 'src-tauri', 'Cargo.toml');
+
+  const rootPkg = readJson(rootPkgPath);
+  if (!rootPkg.version) throw new Error('Root package.json has no version');
+
+  const version = String(rootPkg.version);
+
+  const tauriConf = readJson(tauriConfPath);
+  tauriConf.version = version;
+  writeJson(tauriConfPath, tauriConf);
+
+  updateCargoTomlVersion(cargoTomlPath, version);
+
+  console.log(`Synced Tauri version to ${version}`);
+} catch (e) {
+  console.error('sync-version failed:', e?.message || e);
+  process.exit(1);
+}