feat(ui): a Claude-Desktop-style home for every workspace

/workspace?lane=<id> opens on the workspace's home (WorkspaceHome): a prompt
box whose Start opens a new session in the first free pane slot, Recents (a
live session attaches its pane, any other opens its transcript, nothing
resumes), and Instructions / Memory / Context / Folder. Instructions live in
lanes.instructions, extra folders and uploaded files in the new lane_sources
table (copies under <data dir>/workspace-context/<lane id>/); spawnRun reads
them from the lane's rows and hands Claude --add-dir + an appended system
prompt file, Codex --add-dir + developer_instructions. Memory is read-only.

Every dashboard pane carries AGENTHUB_RUN_ID; hooks forward it and the run
records which session the pane holds (a Claude pane follows /clear and
/resume but not a nested claude -p), so the sidebar and notifications open
the right pane (&run=). Settings loses its Projects group; Worktrees now
decides which worktrees Add folder suggests.

client/src/components/settings/__tests__/WorktreeVisibilitySettings.test.tsx

@@ -2,8 +2,7 @@
  * @file WorktreeVisibilitySettings.test.tsx
  * @description Settings → Worktrees writes the sidebar tree's own prefs key
  * (`agenthub.sidebar.projects`), disables the source rows while untracked
- * worktrees are hidden, and a project's override (`hiddenSourcesFor`) replaces
- * the global list for that project only.
+ * worktrees are not suggested.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
 
@@ -11,7 +10,6 @@ import { beforeEach, describe, expect, it } from "vitest";
 import { render, screen } from "@testing-library/react";
 import userEvent from "@testing-library/user-event";
 import { WorktreeVisibilitySettings } from "../WorktreeVisibilitySettings";
-import { hiddenSourcesFor, readProjectTreePrefs } from "../../../lib/projectTreePrefs";
 
 const stored = () => JSON.parse(localStorage.getItem("agenthub.sidebar.projects")!);
 
@@ -29,15 +27,4 @@ describe("WorktreeVisibilitySettings", () => {
     expect(stored().showUntracked).toBe(false);
     expect(screen.getByRole("switch", { name: "AgentHub-managed worktrees" })).toBeDisabled();
   });
-
-  it("lets a project's own list replace the global one", () => {
-    localStorage.setItem(
-      "agenthub.sidebar.projects",
-      JSON.stringify({ hideSources: ["claude"], projectHideSources: { "/r": [] } })
-    );
-    const prefs = readProjectTreePrefs();
-    expect(hiddenSourcesFor(prefs, "/r")).toEqual([]);
-    expect(hiddenSourcesFor(prefs, "/other")).toEqual(["claude"]);
-    expect(hiddenSourcesFor(prefs, null)).toEqual(["claude"]);
-  });
 });