[FEATURE] FleetView: explicit FleetView command state, on-demand status line, and pre-launch /cd

Feature request: First-class "FleetView" command state + on-demand status line + pre-launch /cd

Area: Claude Code agents / FleetView ("fleet mode")

When working in FleetView, the commands that are specific to that view aren't visually distinguished from ordinary session/project commands, and a couple of view-level capabilities are missing. Three related asks:

1. A distinct "FleetView" command state
Introduce an explicit FleetView state for commands — a third state alongside session and project — and highlight/mark the commands that belong to it so they're easy to spot while in fleet mode. This mirrors how /mode is already surfaced for that view: FleetView-scoped commands should be visually grouped/badged as FleetView-state rather than blending in with session/project commands.

2. Status line observable on demand from FleetView
Allow the status line to be viewed on demand from within FleetView, so fleet-level status is inspectable without leaving the view.

3. /cd before launching a session
Allow /cd from FleetView to set the working directory for a Claude Code session before it's opened — i.e. choose the launch location up front, rather than opening a session and then navigating it there.

Why: In fleet mode it's hard to tell which commands are view-scoped, status isn't readily inspectable, and there's no way to pre-place a session's working directory before opening it. Making FleetView an explicit command state (like /mode) plus these two view affordances would make fleet orchestration much easier to navigate.