Expose rename tab/pane in orchestration and orchestrator skill

[danshapiro]

Summary

The orchestration surface should support renaming both tabs and panes, and the orchestrator skill should expose those operations so agents can use them directly.

Problem

Right now orchestration can manipulate layout/state in useful ways, but it cannot directly express a basic naming action:

• rename the current tab
• rename a specific pane

That makes orchestrated workflows awkward, because an agent can create or rearrange panes/tabs but cannot finish the job by assigning the user-facing names that make the result understandable.

Requested change

Add orchestration support for:

• rename tab
• rename pane

Then expand the orchestrator skill so those actions are discoverable and callable through the skill interface/documentation.

Why this matters

Naming is part of the workflow, not just presentation. If orchestration can create/split/focus panes but cannot rename them, the resulting workspace is harder to understand and harder for agents to leave in a clean state.

Acceptance criteria

• Orchestration exposes an operation for renaming a tab.
• Orchestration exposes an operation for renaming a pane.
• The operation can target the active item and, where applicable, a specific tab/pane identifier.
• The orchestrator skill is updated to expose/document both capabilities.
• A user or agent can complete an end-to-end flow that creates/splits a workspace and then assigns meaningful tab/pane names without manual UI interaction.