Add --json JSON Lines output support

[ocervell]

Summary

This PR adds a global --json option to beanshooter that emits machine readable result
records as JSON Lines (one JSON object per line, easily parseable
with jq). This mirrors the live JSON Lines support recently added to
MANSPIDER and makes it much
easier to consume beanshooter output programmatically.

Records are written live, as they are produced, so the output can be consumed in a
streaming fashion.

Usage

The --json option takes an optional file argument:

• --json – write JSON Lines to stdout. The human readable logging is redirected to
  stderr, so stdout contains valid JSON Lines only.
• --json <file> – append JSON Lines to the given file. Human readable logging stays on stdout.

Result records

type	Emitted by	Notable fields
credentials	brute	host, port, username, password
mbean	list	class, objectName, interesting
enum	enum	check, category, status

Every record additionally carries a type and an ISO-8601 time field.

Example

$ beanshooter brute 172.17.0.2 1099 --ssl --json
{"type":"credentials","time":"2026-06-17T15:48:45.148Z","host":"172.17.0.2","port":1099,"username":"controlRole","password":"control"}
{"type":"credentials","time":"2026-06-17T15:48:45.221Z","host":"172.17.0.2","port":1099,"username":"monitorRole","password":"monitor"}

$ beanshooter enum 172.17.0.2 1099 --ssl --json
{"type":"enum","time":"2026-06-17T15:48:46.543Z","check":"unauthorized-access","category":"vulnerability","status":"non-vulnerable"}
{"type":"enum","time":"2026-06-17T15:48:46.604Z","check":"preauth-deserialization","category":"vulnerability","status":"non-vulnerable"}

Implementation notes

• New JsonLogger class in the io package handles record serialization (no new
  dependencies – a small, self-contained JSON writer is used) and output routing.
• When JSON goes to stdout, Logger transparently redirects human readable output to stderr.
• The enum status records reuse the existing Logger.status* methods, labelled with a
  per-check context set by EnumHelper.

Testing

Built with mvn clean package and verified end-to-end against the
jmx-example-server:2.1 container: --json appears in help, stdout/stderr routing works,
and credentials, mbean, and enum records are emitted as valid, jq-parseable JSON Lines.

🤖 Generated with Claude Code