feat(cli): --journey flag for campus audit traces search #63

Summary

campus audit traces search deliberately shipped without the
server's login-journey filter: PR #55 omitted --journey because
campus-api-python's Traces.search() did not carry it, so the
--dry-run snippets would not have been faithful to what the
library supported. The command help still documents the gap
(campus_cli/audit/traces.py):

The server's login-journey filter is not exposed here yet —
campus-api-python's search() does not carry it.

The blocker is now resolved: campus-api-python#110 added the
keyword-only journey_id filter to Traces.search() (merged in
campus-api-python#111), matching the server's /audit/v1/traces/search?journey_id=…
route (campus#803, shipped in campus#812 on weekly).

Proposed change

In campus_cli/audit/traces.py traces_search:

• Add journey: Optional[str] = typer.Option(None, "--journey", help="Filter by login-journey ID") alongside --user/--client/--api-key-id.
• Pass journey_id=journey through to api.traces.search(...).
• Include "journey_id": journey in the --dry-run kwargs dict (None values are already dropped by _query_operation).
• Drop the "not exposed here yet" paragraph from the docstring.
• Test: kwarg passthrough mirrors the existing search tests in tests/unit/test_audit.py.

Related

• campus-api-python#110 / #111 — library-side filter (done)
• campus#803 / #812 — server-side journey tag and search filter
• feat(cli): campus audit command group — API-key auth, key management, trace queries #54 — parent campus audit command group (this closes its last
  documented gap)