sync: Major UI updates from private repo (Jan 16-24)

Features synced:
- UI Panels Refactor: flexible pane system with ChatPane, NodePane,
  DimensionsPane, WorkflowsPane, ViewsPane, MapPane
- Source Content Reader: content type detection + 4 formatters
  (transcript, book, markdown, raw)
- Source Content Search: Cmd+F search in Source Reader
- Feed Layout Overhaul: LeftToolbar, SplitHandle, CollapsedRail
- Map Panel: promoted to first-class pane
- Edge policy simplification: auto-inference + direction correction

New files:
- src/components/panes/* (pane system)
- src/components/layout/CollapsedRail.tsx
- src/components/layout/LeftToolbar.tsx
- src/components/layout/SplitHandle.tsx
- src/components/focus/source/* (Source Reader + formatters)
- src/components/views/ViewsOverlay.tsx

Updated:
- ThreePanelLayout.tsx (complete refactor)
- FocusPanel.tsx (Source tab integration)
- API routes (dimensions GET, edges auto-inference)
- Database services (nodes, edges, dimensions)

Dependencies added:
- react-markdown
- remark-gfm

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/components/panes/ViewsPane.tsx

@@ -0,0 +1,45 @@
+"use client";
+
+import PaneHeader from './PaneHeader';
+import ViewsOverlay from '../views/ViewsOverlay';
+import type { BasePaneProps, PaneAction, PaneType } from './types';
+
+export interface ViewsPaneProps extends BasePaneProps {
+  onNodeClick: (nodeId: number) => void;
+  onNodeOpenInOtherPane?: (nodeId: number) => void;
+  refreshToken?: number;
+}
+
+export default function ViewsPane({
+  slot,
+  isActive,
+  onPaneAction,
+  onCollapse,
+  onSwapPanes,
+  onNodeClick,
+  onNodeOpenInOtherPane,
+  refreshToken
+}: ViewsPaneProps) {
+  const handleTypeChange = (type: PaneType) => {
+    onPaneAction?.({ type: 'switch-pane-type', paneType: type });
+  };
+
+  return (
+    <div style={{
+      display: 'flex',
+      flexDirection: 'column',
+      height: '100%',
+      background: 'transparent',
+      overflow: 'hidden'
+    }}>
+      <PaneHeader slot={slot} onCollapse={onCollapse} onSwapPanes={onSwapPanes} />
+      <div style={{ flex: 1, overflow: 'hidden' }}>
+        <ViewsOverlay
+          onNodeClick={onNodeClick}
+          onNodeOpenInOtherPane={onNodeOpenInOtherPane}
+          refreshToken={refreshToken}
+        />
+      </div>
+    </div>
+  );
+}