Fix: interactive mode exits after first prompt

[Mostafa-M-Hussein]

Problem

In interactive mode the CLI quits immediately after the first response is printed. The deepseek-cli > prompt never comes back. The chat <prompt> subcommand is not affected.

Repro

1. export DEEPSEEK_API_KEY=...
2. deepseek-cli
3. type a prompt, press Enter
4. response prints, then process exits with Goodbye! 👋

Tested on Node 22, 24, 25.

Cause

In src/commands/interactive.ts the 'line' handler starts an ora spinner inside the await:

const spinner = ora('Thinking...').start();
const response = await api.complete(trimmed);
spinner.stop();

ora hooks process.stdin to manage cursor visibility. On Node 22+ the way it releases stdin on .stop() leaves the stream paused/detached, and readline reads EOF on the next tick. That fires rl.on('close'), which calls process.exit(0). So the very first start/stop cycle is enough to kill the session.

Fix

Pause readline while the spinner is running, resume in finally. Three lines, no behavior change otherwise.

rl.pause();
const spinner = ora('Thinking...').start();
try {
  ...
} finally {
  rl.resume();
}

Verified

• npm run build clean
• interactive mode now keeps the prompt across many prompts, exit and Ctrl+C still work
• single-shot chat command unchanged