feat: v2.5.4 — Query Explorer folded into Sessions, Windows picker and paths

- Sessions page tabs: Sessions · Events · Agents. QueryExplorer.tsx became
  AgentsTable.tsx (agents only — sessions and events already had tabs);
  /query redirects to /sessions?view=agents and leaves the sidebar.
  GET /api/query is unchanged and still answers all three entities.
- Windows picker opens in front: -EncodedCommand script spends the hidden
  first ShowWindow that windowsHide gives the process, then brings the TopMost
  owner forward via AttachThreadInput (v2.5.3's owner was itself hidden).
- Session page Resume/Fork/Open pane: owningLane and sessionWorktreeName
  match Windows folders (either separator), with a test.

client/src/components/Sidebar.tsx

@@ -69,7 +69,6 @@ import {
   ChevronUp,
   ChevronDown,
   FolderTree,
-  TableProperties,
 } from "lucide-react";
 import type { LucideIcon } from "lucide-react";
 import { api } from "../lib/api";
@@ -84,7 +83,6 @@ function isUpdatePayload(x: unknown): x is UpdateStatusPayload {
 const NAV_KEYS = [
   { to: "/", icon: LayoutDashboard, key: "nav:dashboard" },
   { to: "/sessions", icon: FolderOpen, key: "nav:sessions" },
-  { to: "/query", icon: TableProperties, key: "nav:query" },
 ] as const;
 
 // SmartGift wordmark, replacing the old text subtitle. Remote URLs: the logo is