feat(cli): add --yes flag to onboard for non-interactive quickstart

Skip the setup path prompt and auto-start the server when --yes is
passed, enabling fully non-interactive onboarding with local defaults.
Opens the browser automatically on server listen.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cli/src/index.ts

@@ -40,6 +40,7 @@ program
   .description("Interactive first-run setup wizard")
   .option("-c, --config <path>", "Path to config file")
   .option("-d, --data-dir <path>", DATA_DIR_OPTION_HELP)
+  .option("-y, --yes", "Accept defaults (quickstart + start immediately)", false)
   .option("--run", "Start Paperclip immediately after saving config", false)
   .action(onboard);