lanes start: new lane worktrees stop at the project-trust prompt #188

Problem

lanes start <ID> creates a fresh worktree for the lane and launches pi in it. When the repository contains project resources (.pi/, .agents/skills), pi asks the project-trust question on startup because the new worktree path has no saved trust decision and defaultProjectTrust is ask. The lane then sits at the prompt until a human answers it, which defeats unattended lane launches.

Expected

A lane started by lanes for a repository that was explicitly added with lanes add starts without a trust prompt.

Proposal

• lanes start/resume launches pi with --approve for worktrees it created for an explicitly added repository (in line with how --preapprove-mcp handles project MCP servers), or writes a saved trust decision for that exact worktree path before launch.
• Keep it opt-in per lanes folder (for example launch.approveProjectTrust: true in lanes.json, offered by lanes init), so folders with repositories from outside the owner's control keep the prompt.
• A spec that lanes start on a repository with a .pi/settings.json produces a launch command that does not prompt for trust.

Workaround

A saved trust decision for the shared worktree parent directory covers new lane worktrees, since the closest saved parent decision applies.

Status

State: In progress
Branch: -
Scope: Opt-in project-trust approval for lane worktrees started by lanes
Plan: lanes run.ts adds pi's --approve flag only when lanes.json opts in (launch.approveProjectTrust, default false; lanes init --approve-project-trust) and the launch is a non-coordinator lane in a worktree lanes created under worktreesDir; any error means no approval. Specs, README trust boundary, dist rebuild.
Delivered: Nothing yet.
Remaining: To be confirmed.
Follow-ups: None.