Add --quiet flag support for JSON output

[hermanngeorge15]

Problem

--quiet only filters warnings from text output. When using --format json --quiet, warnings are still included in the JSON.

Proposal

When --quiet is used with --format json, filter warning results from the JSON output as well. Keep the warningCount field accurate to the filtered results.

Acceptance Criteria

• --format json --quiet excludes warning results from JSON
• warningCount reflects filtered count
• Text formatter behavior unchanged
• Test added

Labels

enhancement, cli