sessions

## Before Making Any Changes **MANDATORY:** Before writing or modifying any code in `src/vs/sessions/`, you **must** read these documents: 1. **`.github/instructions/coding-guidelines.instructions.md`** — Naming conventions, code style, string localization, disposable management, and DI patterns. 2. **`.github/instructions/source-code-organization.instructions.md`** — Layers, target environments, dependency injection, and folder structure conventions. Then read the relevant spec for the area you are changing (see table below). If you modify the implementation, you **must** update the corresponding spec to keep it in sync. ## Specification Documents | Document | Path | When to read | |----------|------|-------------| | Layer rules | `src/vs/sessions/LAYERS.md` | Before adding any cross-module imports. Defines the internal layer hierarchy (`core` → `services` → `contrib` → `providers`) with ESLint-enforced import restrictions. Key rule: `contrib/*` must NOT import from `contrib/providers/*`. | | Layout spec | `src/vs/sessions/LAYOUT.md` | Before changing any part, grid structure, titlebar, or CSS. Documents the fixed grid layout (Sidebar \| ChatBar \| AuxiliaryBar), part positions, the modal editor system, per-session layout state persistence, and the titlebar's three-section design. | | Layout controller spec | `src/vs/sessions/LAYOUT_CONTROLLER.md` | Before changing `LayoutController` or per-session layout state. Details how the auxiliary bar, panel, and editor working s...