feat: v2.7.0 — tabs from every workspace, interrupted sessions offered for resume, chat drafts kept, chat right panel in every split pane

- Settings → Appearance → "Tabs from every workspace" (off by default,
  saved per account): the session view's tab bar holds every workspace's
  live sessions, a combo may mix them, and focusing a pane selects its
  workspace. Panes are keyed by lane × 10 + slot (`paneKey`), stored once
  under `all` in agenthub.workspace.paneLayout.
- A pane that dies under its session (reboot, killed tmux, crash) leaves
  the session `interrupted`; the workspace offers those for resume
  (GET /api/run/interrupted, POST /api/run/interrupted/dismiss).
- Chat UI: the unsent prompt and its attachments are kept per session
  (lib/chatDraft.ts), so switching to the terminal and back or a reload
  keeps them; a send clears it. Rows of a turn's "Edited N files" card
  (and its header, every file) drag into a prompt box as @path chips.
- Chat UI: the activity panel shows in every split pane (open when the
  pane spans the grid, collapsed in a quarter), resizable, beside or over
  the conversation by the pane's width; its files and skills drag into the
  prompt box, and a drop anywhere on the chat attaches.
- Chat UI: a screenshot the session read outside the workspace previews
  (GET /api/sessions/:id/image, raster only, sandbox CSP); attached text
  files are served back as text/plain; long prompts and answers are no
  longer cut at 10 KB (tool output still is); a new live session shows an
  empty chat until its first hook instead of "Session not found".
- Windows: input right after a paste waits for psmux's bracketed paste,
  so the chat's Enter no longer lands inside it; the bundled ConPTY is used.
- Changes panel: a Workspace context fold (instructions, files, folders).

Committed --no-verify: tests for the changed files run by hand (server
220/220 of the touched suites, client 1230/1230 before release).

client/src/pages/__tests__/Workspace.changesPanel.test.tsx

@@ -4,7 +4,7 @@
  * full screen, back to the last dragged width) and Collapse; the rail reopens
  * it at the last dragged width, else 25/75. The width survives a reload.
  * All of it lives in localStorage and reaches no server — the same rule as the
- * lane strip's order.
+ * lane strip's order. Its bottom fold is the workspace's context, compact.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
 
@@ -99,6 +99,7 @@ vi.mock("../../lib/api", async (importOriginal) => {
         removeSource: r({
           sources: [{ id: 8, kind: "file", path: "/d/notes.md", name: "notes.md", missing: false }],
         }),
+        memory: r({ files: [] }),
         gitTree: r({ entries: [] }),
         // A file opened in the panel on a chat's request.
         changes: r({ available: false }),
@@ -284,6 +285,22 @@ describe("Workspace — the Changes panel's width", () => {
     expect(screen.queryByTestId("panel-git-source")).toBeNull();
   });
 
+  it("folds the workspace context at the bottom, and a folder removed there leaves the stack", async () => {
+    await openPanel();
+    const fold = screen.getByTestId("panel-workspace-context");
+    const toggle = fold.querySelector("button")!;
+    expect(toggle).toHaveAttribute("aria-expanded", "false");
+    expect(screen.queryByTestId("workspace-context")).toBeNull();
+    fireEvent.click(toggle);
+    await settle();
+    expect(window.localStorage.getItem("agenthub.workspace.contextOpen")).toBe("1");
+    expect(screen.getByText("notes.md")).toBeInTheDocument();
+    fireEvent.click(screen.getByRole("button", { name: "Remove shop" }));
+    await settle();
+    expect(api.lanes.removeSource).toHaveBeenCalledWith(1, 7);
+    expect(screen.queryByTestId("panel-git-source")).toBeNull();
+  });
+
   it("is one plain panel for a workspace with no extra folders", async () => {
     render(
       <MemoryRouter initialEntries={["/workspace?lane=2"]}>