Make batch a complete, structured read-only query transport

[Widthdom]

Summary

Bring safe read-only navigation/audit commands into batch dispatch and embed child JSON as JSON rather than escaped strings.

Current v1.38.0 evidence / reproduction

• Batch rejects read-only goto and audit commands despite describing support for query and read-only discovery commands.
• batch --json-summary wrapping status --json emits the child object as an escaped stdout string, requiring a second parse and expanding payload size.

Impact

Editor and agent clients cannot batch common navigation/audit operations and lose the benefits of a typed batch response.

Suggested direction / acceptance criteria

• Maintain a schema-driven allowlist of side-effect-free commands including goto and audit.
• Parse successful JSON/NDJSON child output into typed result fields while retaining raw text for non-JSON output.
• Preserve per-item exit/error metadata and bound total batch output.

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Dogfooding candidate IDs: Q046, Q047, R013. Verified against cdidx v1.38.0 at commit 2919bfc9b1b83cfa7ae1d964845d0f9ffca002d1.

[Widthdom]

Work started on branch fix-issue4582.