CLI Improvements: Robustness & Better Error Handling

I've reviewed the codebase and identified a few areas where the current implementation could be more robust and easier to debug. This issue tracks the following improvements:

1. Fix Potential Crash in getFilepath (src/cli.ts)

Problem: Currently, getFilepath checks only two possible filenames (the default and one with a random ID). If by chance both files exist, the non-null assertion (!) at the end of the chain will cause the program to crash.

Proposed Fix:

• Implement a loop or more robust retry mechanism to guarantee a unique filename is always generated.

2. Improve Error Handling in lstat Helper (src/cli.ts)

Problem: The lstat helper currently swallows all errors. If a permission error (EPERM) or other system error occurs, it is treated indiscriminately as "file not found". This masks actual system issues that the user should know about.

Proposed Fix:

• Update the try-catch block to only catch ENOENT errors and re-throw all others.

3. Address Empty Catch Blocks in kill (src/core.ts)

Problem: The kill function contains multiple empty try-catch blocks. While ignoring errors when killing a non-existent process is valid, completely swallowing them makes debugging difficult.

Proposed Fix:

• Add comments explaining why these errors are ignored (e.g., 'ignore if process is already dead').
• Or log them when verbose mode is enabled.