Parse stack traces and display file/line context

[naheel0]

Title: Parse stack traces and display file/line context

Problem

CLI output currently shows only the error message; users need a quick pointer to the file and line that caused the error.

Proposed change

Add a stack trace parser that extracts file path, line, column, and function name from Node-style stack traces. Show a small source snippet around the error location when available and expose this info in JSON output.

Files to change

• add lib/stack-parser.js
• update lib/formatter.js to include location + snippet
• update bin/index.js to pass stack to matcher/formatter

Tasks

• Implement parseStackTrace(errorString) to extract frames (file, line, col, function).
• Implement sourceSnippet(filepath, line, radius) to read a safe context sample.
• Add --context flag to run/analyze to enable snippet printing.
• Add tests for common Node.js stack formats.

Acceptance criteria

• For input with a stack trace, the CLI prints the location and a 5-line snippet.
• JSON output includes a locations array with frame details.

Labels: enhancement, medium-priority