Adding a Workspace tab

The Workspace has several kinds of tab (TabKind in packages/core/src/workspace/types.ts), and they come in three shapes. Pick the one that matches what you are adding.

Two classes split the work (see architecture): TabHost (packages/desktop/src/core/tab-host.ts) holds the tab state in the core, with no Electron import, and ViewReconciler (packages/desktop/src/view-reconciler.ts) follows that state in the Electron app and keeps one WebContentsView per tab that hasView says should have one. A new tab is almost always a change to the first; the second follows on its own.

Shape 1 — a hosted web app (Editor, Database, Cluster)

Something that already exists and speaks HTTP. Spawn it per project, open its URL as a tab. The whole cost is a manager.

1. TabKind gains the name; HOSTED_APP_LABELS in core/tab-host.ts gains its tab-strip label.
2. A manager in platform, modelled on code-server.ts: open(project) reuses or spawns, stopAll() kills everything on quit, every side effect injected.
3. A handler in ipc.ts, wired into the core in core/compose.ts and keyed by its channel in dispatch.ts, that resolves the project name to a path, wraps the manager's developer-facing detail behind one bilingual headline, and opens the tab with TabHost.open(project, url, kind). Classify its channel in remote-policy.ts; there is no default, so forgetting is a compile error.
4. A button in the workspace head that reuses an existing tab before opening a second.

Bind it to loopback if you possibly can. code-server does; DbGate cannot, which is why that one carries a generated login instead.

Shape 2 — a surface the renderer draws (Terminal, API, Docker)

No hosted page at all: state in the core, pixels in the renderer.

1. TabKind gains the name, VIEWLESS_KINDS in core/tab-host.ts gains it (so hasView is false and the reconciler never builds a view), and RENDERER_DRAWN in renderer/workspace.ts gains it too — that set is what hides the page slot, which is a flex sibling that would otherwise split the height with your pane.
2. An openX(project) method on TabHost, like openTerminal, openApi and openDocker, creates the tab through its private #openViewless. Because the tab has no view, the ViewReconciler hides every hosted page while it is active, for free.
3. Your pane renders from workspace state — renderX(tabs, activeTabId, selectedProject) — and shows only when the active tab is yours and belongs to the selected project. The second half matters: switching to a project with no open tab leaves the previous project's tab active in the store, and the reconciler hides its views (hideAll) behind a flag the renderer cannot see.
4. Eviction already leaves it alone. The MAX_TABS cap counts only tabs hasView says hold a page, because it bounds Chromium processes; closing a viewless tab would free nothing and lose the process behind it.

Shape 3 — an ordinary page

TabHost.open(project, url). Nothing else to do.

In every case

• The chrome rule (kind !== "web") hides the address bar and bookmarks already. You do not need to touch it.
• A hosted app's title is fixed at open; a page's title follows the document.
• If your tab owns a child process, kill it in close() and on quit.
• Keep core/tab-host.ts free of Electron (core/no-electron.test.ts): the headless daemon runs it too. Anything that needs a window belongs in the reconciler or desktop-only.ts.
• Add the new ids to index.html and let id-contract.test.ts check them.