fix: security and documentation fixes

- fix(utils.js): prevent command injection in commandExists() by using
  spawnSync instead of execSync with string interpolation, and validate
  input to only allow alphanumeric chars, dash, underscore, dot (#42)

- fix(utils.js): add security documentation to runCommand() warning
  against passing user-controlled input

- fix(setup-package-manager.js): replace <script> and <binary> with
  [script-name] and [binary-name] to avoid XSS scanner false positives (#43)

- fix(doc-updater.md): replace invalid 'npx ts-morph' with correct
  'npx tsx scripts/codemaps/generate.ts' since ts-morph is a library,
  not a CLI tool (#51)

Fixes #42, #43, #51

scripts/setup-package-manager.js

@@ -89,8 +89,8 @@ function detectAndShow() {
   console.log('');
   console.log('Commands:');
   console.log(`  Install: ${pm.config.installCmd}`);
-  console.log(`  Run script: ${pm.config.runCmd} <script>`);
-  console.log(`  Execute binary: ${pm.config.execCmd} <binary>`);
+  console.log(`  Run script: ${pm.config.runCmd} [script-name]`);
+  console.log(`  Execute binary: ${pm.config.execCmd} [binary-name]`);
   console.log('');
 }