feat(web): add global app status surface (#1869)

* feat(web): add app status bar

* feat(web): add app status bar visibility toggle

* feat(web): persist status bar item order

* fix(web): refine app status bar behavior

* fix(web): polish app status bar presentation

* test(web): split plugin slot coverage groups

* fix(web): address status surface review feedback

* fix(web): stabilize status bar overlay tests

docs/public/plugins-authoring.md

@@ -303,7 +303,8 @@ interface PluginRegistry {
   registerSettingsRoute(path: string, Component: React.ComponentType): void;
   // Named slot injection. Initial slots: "task-sidebar", "settings-nav",
   // "main-nav-footer", "chat-input-actions", "chat-top-bar", "main-top-bar",
-  // "plugin-settings" (see "Named slots" below).
+  // "app-status-bar-left", "app-status-bar-right", and "plugin-settings"
+  // (see "Named slots" below).
   registerComponent(slot: string, Component: React.ComponentType<{ slotProps?: unknown }>): void;
   // WS action handler, bridged into the existing lib/ws dispatch.
   registerWsHandler(action: string, handler: (payload: unknown) => void): void;
@@ -395,6 +396,8 @@ plugins at once. Available slots:
 | `chat-input-actions` | Chat composer toolbar, beside the model picker, mic, and send button | `{ taskId, taskTitle, activeSessionId, sessionIds }` |
 | `chat-top-bar` | Session top bar, beside the CPU/DB metrics and the document/editor/debug controls | `{ taskId, taskTitle, workspaceId, activeSessionId, sessionIds }` |
 | `main-top-bar` | Default app top bar (Home / Kanban / Tasks), beside the CPU/DB metrics and the view/display controls | `{ workspaceId, workspaceLabel, currentPage }` |
+| `app-status-bar-left` | Default-left item in the global status surface | `AppStatusBarSlotProps` |
+| `app-status-bar-right` | Default-right item in the global status surface | `AppStatusBarSlotProps` |
 | `plugin-settings` | A plugin's own settings page (**Settings > Plugins > `<plugin>`**), at the top above the settings form | `{ pluginId, status }` |
 
 `plugin-settings` is the one exception to "every plugin's component renders":
@@ -467,8 +470,7 @@ example.
 ### Session top bar
 
 Register a `chat-top-bar` component to surface at-a-glance status in the
-session top bar, beside the first-party CPU/DB metrics and the
-document/editor/debug controls. The host passes the current context as
+session top bar, beside first-party document/editor/debug controls. The host passes the current context as
 `slotProps`:
 
 ```ts
@@ -545,6 +547,53 @@ show.
 registry.registerComponent("plugin-settings", makeSettingsStatus(host));
 ```
 
+### Global Status bar
+
+Register `app-status-bar-left` or `app-status-bar-right` for app-wide, compact
+status UI. Kandev mounts exactly one presentation: a 24 px bar on tablet and
+desktop, or an in-flow Status drawer section on phone. Keep bar content small;
+render a touch-usable row when `presentation` is `"mobile-drawer"`.
+
+```js
+function StatusContribution({ slotProps }) {
+  const { placement, presentation, activeTaskId } = slotProps ?? {};
+  return host.jsx(
+    "span",
+    { className: presentation === "bar" ? "truncate text-xs" : "block min-h-11 px-3 py-2" },
+    `${placement}: ${activeTaskId ?? "no active task"}`,
+  );
+}
+
+registry.registerComponent("app-status-bar-left", StatusContribution);
+registry.registerComponent("app-status-bar-right", StatusContribution);
+```
+
+Each contribution receives this exact context:
+
+```ts
+type AppStatusBarSlotProps = {
+  placement: "left" | "right";
+  presentation: "bar" | "mobile-drawer";
+  density: "full" | "compact";
+  pathname: string;
+  activeWorkspaceId: string | null;
+  activeTaskId: string | null;
+  activeSessionId: string | null;
+};
+```
+
+The IDs are hints; use `host.store` for full records. Each component registration
+is one opaque item: Kandev does not inspect or separately reorder its children.
+The slot chooses the default side. A user can Cmd-drag (macOS) or Ctrl-drag
+(other desktop platforms) with a mouse across the full bar, and Kandev preserves
+that backend-owned order across reloads, restarts, and plugin disable/enable.
+Phone lists the saved left sequence followed by the saved right sequence and does
+not offer drag ordering. There is no keyboard-arrow, touch, or plugin-priority
+ordering API. Enable, disable, and uninstall update the live surface without a
+reload, and each contribution has its own error boundary. A full-bleed route
+(`topbar: false`) owns its own chrome; mount the host Status trigger there if that
+route should expose Status.
+
 ## Three integration patterns
 
 Both example repos are full, working plugins — read them rather than