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/write-build-flag.js

@@ -0,0 +1,54 @@
+#!/usr/bin/env node
+import fs from 'fs';
+import path from 'path';
+
+const cmd = process.argv[2] || 'set';
+const repoRoot = process.cwd();
+const dst = path.join(repoRoot, 'src', 'build-info.json');
+
+function getPackageVersion() {
+  try {
+    const pkgPath = path.join(repoRoot, 'package.json');
+    const pkg = JSON.parse(fs.readFileSync(pkgPath, 'utf8'));
+    return pkg && pkg.version ? String(pkg.version) : null;
+  } catch (_) {
+    return null;
+  }
+}
+
+function computeDebugFlag() {
+  const envVal = process.env.RADIO_DEBUG_DEVTOOLS;
+  if (envVal === '1' || envVal === 'true') return true;
+  const arg = (process.argv[3] || '').toLowerCase();
+  return arg === 'debug' || arg === '--debug';
+}
+
+if (cmd === 'set') {
+  try {
+    const version = getPackageVersion();
+    const debug = computeDebugFlag();
+    const payload = {
+      version,
+      debug,
+      builtAt: new Date().toISOString(),
+    };
+    fs.writeFileSync(dst, JSON.stringify(payload, null, 2) + '\n', 'utf8');
+    console.log(`Wrote build-info.json (debug=${debug}${version ? `, version=${version}` : ''})`);
+    process.exit(0);
+  } catch (e) {
+    console.error('Failed to write build-info.json', e);
+    process.exit(1);
+  }
+} else if (cmd === 'clear') {
+  try {
+    if (fs.existsSync(dst)) fs.unlinkSync(dst);
+    console.log('Removed build-info.json');
+    process.exit(0);
+  } catch (e) {
+    console.error('Failed to remove build-info.json', e);
+    process.exit(1);
+  }
+} else {
+  console.error('Unknown command:', cmd);
+  process.exit(2);
+}