Support node and jq command filtering��#3800

From rtk discover on real usage (26 sessions, 30 days):

• node — 18 calls unhandled (e.g. node --test test/policies.test.cjs)
• jq — 20 calls unhandled combined (15 jq -r, 5 jq empty)

Both produce large stdout (test output, JSON) that could benefit from
rtk-style filtering/truncation. Est. savings not captured since no
rtk equivalent exists yet.