[SakarPaisen]

Closes #2

What changed

• \process_json\ in \src/mcp_tools_lab/tools/json_tool.py\ takes a typed \indent\ argument (default \2). Only \2\ and \4\ are accepted; any other value raises a readable \ValueError. \indent\ is validated for every action, but only formatted output is affected, so existing \minify\ and \�alidate\ behavior is unchanged.
• Docstring updated; \docs/tool-guide.md\ signature and wording updated.
• Existing JSON semantics (keys, numbers, separators, error reporting) are untouched.

Tests

Added to \ ests/test_json_tool.py: default two-space output, explicit \indent=2, \indent=4, nested JSON at both indents, and invalid values (\3, \