feat(web): pin Logging/History/Network as a resizable column (#1616)

Add the ability to "pin" the Logging, History, and Network screens into a
second column on the right of the InspectorView, so a primary screen and a
monitor screen are visible at once (e.g. watch Logs while calling a Tool).

- A "pin as column" button on the Logs/History/Network panel toolbars opens
  the column (shown only when wide + connected).
- The column hosts a MonitoringControls tab row (available monitor tabs +
  close) over the selected embedded screen. Pinning removes the monitor group
  from the header tab bar; closing (x) returns it.
- The divider between the primary area and the column is draggable (pointer +
  keyboard); width is clamped and persisted.
- The split collapses to one column below ~1040px (the ServerListScreen
  single-card breakpoint) and while disconnected, without discarding the pin
  preference — it reopens when wide + connected again.

State (pinned/tab/width) is view-local and persisted via the existing
useLocalStorage pattern, so no new props thread through App and ViewHeader is
unchanged (it just receives a filtered tab list). Screens/panels gain an
`embedded` mode (fills the parent height, drops the 340px filter sidebar) via a
shared EmbeddableScrollArea element.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

clients/web/src/components/elements/PinColumnButton/PinColumnButton.tsx

@@ -0,0 +1,26 @@
+import { ActionIcon } from "@mantine/core";
+import { TbLayoutSidebarRightExpand } from "react-icons/tb";
+
+export interface PinColumnButtonProps {
+  /** Pin this screen into the monitoring column to the right. */
+  onPin: () => void;
+}
+
+/**
+ * Toolbar icon that pins the owning monitor screen (Logs / History / Network)
+ * into the resizable column on the right of the InspectorView (#1616). Distinct
+ * from `PinToggle` (which pins individual history entries) — this one opens a
+ * side column, so it uses a right-sidebar glyph and an "as column" label.
+ */
+export function PinColumnButton({ onPin }: PinColumnButtonProps) {
+  return (
+    <ActionIcon
+      variant="default"
+      size="lg"
+      aria-label="Pin as column"
+      onClick={onPin}
+    >
+      <TbLayoutSidebarRightExpand size={18} />
+    </ActionIcon>
+  );
+}