Reduce default Pinet lanes output verbosity and detail exposure

[gugu91]

Problem

Maintainer feedback: Pinet dispatcher output is still too verbose in operator transcripts. A recent pinet lanes call produced a large response that duplicated long human-readable data.text with full data.details.lanes, including lane metadata and participants.

Some of that example was requested with full:true / JSON for broker inspection, but the operator-facing concern still stands: default and visible Pinet output should not swamp the transcript or expose detailed lane metadata unless explicitly requested.

Why this should be separate from #735 / PR #736

PR #736 is prompt/tool-help/docs-sized guidance about how to use dispatcher args and read Pinet pointers. This issue is behavioral response-shaping/redaction work in dispatcher output paths, especially for lanes, and should be designed/tested separately.

Desired direction

• Default pinet action=lanes should return a short active/ready summary only.
• Omit participants and detailed metadata unless full:true or explicit JSON/detail output is requested.
• Avoid returning duplicated large text + details payloads to visible tool output by default.
• Keep explicit inspection paths available for broker/debug usage.
• Preserve guardrails and existing action-level routing semantics.

Acceptance criteria

• Compact default output for lanes covers the common operator question without flooding transcript context.
• Full lane details remain available through explicit opt-in.
• Tests cover default compact output, explicit full output, and JSON/detail behavior.
• Docs/help clarify when full details are included.
• No secrets, raw local session paths, or sensitive metadata are exposed in default visible output.

[gugu91]

Maintainer clarification to make the contract explicit:

• Default Pinet tool output should be compact, human-readable plain text — not JSON.
• JSON/structured envelopes should require explicit opt-in such as format: "json".
• Default output should not expose the status / data / details / errors / warnings wrapper as JSON in the transcript.
• This applies especially to pinet action=lanes, but should be treated as a general dispatcher/tool response contract.
• Privacy/non-leakage remains central: lane metadata, participants, thread ids, worktree paths, and other detailed internals should not appear in default visible output.

Scope recommendation: keep this separate from #735/#736. PR #736 is prompt/help/docs guidance; this issue needs behavioral response-shaping tests across dispatcher defaults, with explicit opt-in paths preserved for broker/debug inspection.