Removed the global bottom "documents selected" split panel (#370)

* chore(ui): remove unused split panel UI and cleanup layout

* feat(ui): remove global split panel and update LambdaArchitecture parameter

Author: rstrahan

CHANGELOG.md

@@ -9,6 +9,10 @@ SPDX-License-Identifier: MIT-0
 
 - **Configurable Lambda architecture** — New `LambdaArchitecture` parameter (`arm64` or `x86_64`) for all unified pattern Lambda container images. Defaults to `arm64` (Graviton) for best price-performance. Use `x86_64` when deploying with custom base images that only support AMD64. The parameter flows through to CodeBuild (`--platform` flag) and Dockerfile (`FROM` image suffix).
 
+### Removed
+
+- **Global split panel ("documents selected")** — Removed the persistent bottom split panel from the global Web UI layout and deleted the related split-panel components and `use-split-panel` hook. The split-panel was noisy on non-document-list pages and only provided full details for single-document selection; reintroduce as an opt-in, per-page component if needed (recommendation: enable only on `DocumentList`).
+
 ## [0.5.15]
 
 ### Added

src/ui/src/components/document-list/DocumentListSplitPanel.tsx

@@ -10,7 +10,6 @@ import { DocumentsContext } from '../../contexts/documents';
 import { Document } from '../../types/documents';
 
 import useNotifications from '../../hooks/use-notifications';
-import useSplitPanel from '../../hooks/use-split-panel';
 import useGraphQlApi from '../../hooks/use-graphql-api';
 import useAppContext from '../../contexts/app';
 
@@ -27,7 +26,6 @@ import { appLayoutLabels } from '../common/labels';
 import Navigation from './navigation';
 import Breadcrumbs from './breadcrumbs';
 import ToolsPanel from './tools-panel';
-import SplitPanel from './documents-split-panel';
 import ConfigurationLayout from '../configuration-layout';
 import PricingLayout from '../pricing-layout';
 import CapacityPlanningLayout from '../capacity-planning/CapacityPlanningLayout';
@@ -90,8 +88,6 @@ const GenAIIDPLayout = ({ children, tools }: GenAIIDPLayoutProps): React.JSX.Ele
     abortWorkflows,
   } = useGraphQlApi({ initialPeriodsToLoad });
 
-  const { splitPanelOpen, onSplitPanelToggle, splitPanelSize, onSplitPanelResize } = useSplitPanel(selectedItems);
-
   const documentsContextValue = {
     documents,
     getDocumentDetailsFromIds,
@@ -123,11 +119,6 @@ const GenAIIDPLayout = ({ children, tools }: GenAIIDPLayoutProps): React.JSX.Ele
         tools={tools ?? <ToolsPanel />}
         toolsOpen={toolsOpen}
         onToolsChange={({ detail }) => setToolsOpen(detail.open)}
-        splitPanelOpen={splitPanelOpen}
-        onSplitPanelToggle={onSplitPanelToggle}
-        splitPanelSize={splitPanelSize}
-        onSplitPanelResize={onSplitPanelResize}
-        splitPanel={<SplitPanel />}
         content={
           children || (
             <Routes>