feat: --resume And --save Command-line Arguments

[shuxueshuxue]

TLDR

This PR adds --resume and --save command-line arguments to enable checkpoint-based conversation persistence in non-interactive mode. Users can now save their conversation history to named checkpoints and resume from them later.
This is crucial for developing sdk similar to Claude Code.

Dive Deeper

This implementation adds two new features to the CLI:

1. --resume - Loads a previous conversation from a checkpoint file
   - Accepts either a checkpoint tag (e.g., "session1") or a full file path
   - Restores the full conversation context so the model can continue where it left off
2. --save - Saves the current conversation to a checkpoint file
   - Saves the complete conversation history in the logger checkpoint format
   - Can be used together with --resume to continue and save sessions
   - Checkpoint files are stored in ~/.qwen/tmp//checkpoint-.json

The implementation follows the existing patterns in the codebase:

• Added new fields to CliArgs interface and ConfigParameters
• Integrated with yargs for command-line parsing
• Added getter/setter methods in the Config class
• Implemented load/save logic in nonInteractiveCli.ts

Reviewer Test Plan

To test this feature:

1. Basic save and resume:

# Save a conversation
  qwen -p "My favorite color is blue" --save "test1"

  # Resume and continue
  qwen -p "What's my favorite color?" --resume "test1"
  # Should respond with "blue"

2. Chaining conversations:

  # Start a conversation
  qwen -p "Remember that I like pizza" --save "food"

  # Continue and save to new checkpoint
  qwen -p "I also enjoy sushi" --resume "food" --save "food2"

  # Load the extended conversation
  qwen -p "What foods do I like?" --resume "food2"
  # Should mention both pizza and sushi

3. Error handling:

  # Try to resume non-existent checkpoint
  qwen -p "Hello" --resume "nonexistent"
  # Should show clean error message

4. Full path support:

  # Save with custom path
  qwen -p "Test message" --save "/tmp/my-checkpoint.json"

  # Resume from full path
  qwen -p "Repeat my message" --resume "/tmp/my-checkpoint.json"

Testing Matrix

	🍏	🪟	🐧
npm run	❓	✅	✅
npx	❓	❓	❓
Docker	❓	❓	❓
Podman	❓	-	-
Seatbelt	❓	-	-

[bl-ue]

Hi! FYI—a series of PRs are being merged which add automatic save/resume support to Gemini CLI, as well as a --resume command line argument, and a bunch more. See google-gemini/gemini-cli#4401 for an analysis of the implementation and links to the PRs. (I'm noting this down in case it will make merging this #201 PR difficult.)