fix: preserve spaces in arguments during encryption/decryption

[12end]

Description

This PR fixes issue #19: "Bug：包含空格的参数值在加解密后会被错误拆分，导致参数个数/内容丢失"

Problem

The original code used strings.Join(args, " ") and strings.Split(output, " ") to serialize/deserialize arguments. When an argument value contained spaces, it would be incorrectly split during decryption, losing the original argument count and content.

For example:

• Input: --name "hello world"
• Expected after decryption: ["--name", "hello world"]
• Actual (buggy): ["--name", "hello", "world"]

Solution

Each argument is now base64-encoded individually before being joined with a newline separator. This ensures:

1. Spaces within arguments are preserved (base64 doesn't use spaces)
2. Empty arguments are preserved (base64 of empty string is non-empty)
3. The original argument count and content are fully restored

Changes

• cargs.go: Modified encryption to base64-encode each argument individually, joined by newline
• cargs.go: Modified decryption to split by newline and base64-decode each argument
• cargs_test.go: Added comprehensive tests for various edge cases
• go.mod/go.sum: Added for dependency management

Testing

All tests pass:

• Simple args without spaces
• Args with single space
• Args with multiple consecutive spaces
• Args with leading and trailing spaces
• Empty string arguments
• Special characters
• Realistic command line scenarios

Fixes #19

@12end can click here to continue refining the PR