Add --json output flag for batch query results #263

Problem

litecli already supports --csv and --table for batch output (used with -e and stdin queries), but it has no equivalent --json flag. The underlying cli_helpers library already ships a json_output_adapter.py, so the formatter is available — only the CLI flag is missing.

Solution

Add a --json flag parallel to the existing --csv and -t/--table options on the root cli command. In the -e and stdin branches of litecli/main.py, set litecli.formatter.format_name = "json" next to the existing format_name = "csv" / "tsv" assignments. The change should be ~5 lines.

A table_format = "json" entry could also be accepted in ~/.config/litecli/config, mirroring the existing table_format = "csv" knob.

Use case

Scripting and CI pipelines:

litecli mydb.sqlite -e "select id, name from users" --json | jq '.[] | select(.name | startswith("a"))'

…instead of having to pipe --csv through jq -r '@csv' round-tripping.