fix: orchestrator button + Pi SDK session error

- Move leftSidebarMode from URL state to local useState in unified-shell,
    avoiding force-dynamic router round-trip that made the button appear broken                                           - Replace fileURLToPath(new URL(..., import.meta.url)) with process.cwd()
    in bb-pi-bootstrap.ts — import.meta.url is a webpack:// URL in Next.js,
    causing cross-realm TypeError when passed to Node.js fileURLToPath()

src/hooks/use-url-state.ts

@@ -3,10 +3,13 @@
 import { useCallback, useEffect, useMemo, useState } from 'react';
 import { useSearchParams, useRouter } from 'next/navigation';
 
-export type ViewType = 'social' | 'graph' | 'activity';
+export type ViewType = 'social' | 'graph';
 export type PanelState = 'open' | 'closed';
 export type DrawerState = 'open' | 'closed';
 export type GraphTabType = 'flow' | 'overview';
+export type LeftSidebarMode = 'epics' | 'orchestrator';
+export type LeftPanelStatusFilter = 'all' | 'ready' | 'in_progress' | 'blocked' | 'deferred' | 'done';export type LeftPanelPriorityFilter = 'all' | 'P0' | 'P1' | 'P2' | 'P3' | 'P4';export type LeftPanelPresetFilter = 'all' | 'active' | 'blocked_agents';export interface LeftPanelFilters {  status: LeftPanelStatusFilter;  priority: LeftPanelPriorityFilter;  preset: LeftPanelPresetFilter;  hideClosed: boolean;
+  query: string;}
 
 export interface UrlState {
   view: ViewType;
@@ -22,6 +25,9 @@ export interface UrlState {
   leftPanel: PanelState;
   setLeftPanel: (state: PanelState) => void;
   toggleLeftPanel: () => void;
+  leftSidebarMode: LeftSidebarMode;
+  setLeftSidebarMode: (mode: LeftSidebarMode) => void;
+  toggleLeftSidebarMode: () => void;
   rightPanel: PanelState;
   setRightPanel: (state: PanelState) => void;
   toggleRightPanel: () => void;
@@ -42,11 +48,13 @@ const DEFAULT_LEFT_PANEL: PanelState = 'open';
 const DEFAULT_RIGHT_PANEL: PanelState = 'open';
 const DEFAULT_DRAWER: DrawerState = 'closed';
 const DEFAULT_GRAPH_TAB: GraphTabType = 'overview';
+const DEFAULT_LEFT_SIDEBAR_MODE: LeftSidebarMode = 'epics';
 
-const VALID_VIEWS: ViewType[] = ['social', 'graph', 'activity'];
+const VALID_VIEWS: ViewType[] = ['social', 'graph'];
 const VALID_PANELS: PanelState[] = ['open', 'closed'];
 const VALID_DRAWERS: DrawerState[] = ['open', 'closed'];
 const VALID_GRAPH_TABS: GraphTabType[] = ['flow', 'overview'];
+const VALID_LEFT_SIDEBAR_MODES: LeftSidebarMode[] = ['epics', 'orchestrator'];
 
 const PANEL_STORAGE_KEYS = {
   left: 'bb.ui.leftPanel',
@@ -78,6 +86,13 @@ function isBlockedEnabled(value: string | null): boolean {
   return value === '1' || value === 'true';
 }
 
+function parseLeftSidebarMode(value: string | null): LeftSidebarMode {
+  if (!value || !VALID_LEFT_SIDEBAR_MODES.includes(value as LeftSidebarMode)) {
+    return DEFAULT_LEFT_SIDEBAR_MODE;
+  }
+  return value as LeftSidebarMode;
+}
+
 export function parseUrlState(
   searchParams: URLSearchParams,
   defaults: PanelDefaults = {
@@ -91,6 +106,7 @@ export function parseUrlState(
   agentId: string | null;
   epicId: string | null;
   leftPanel: PanelState;
+  leftSidebarMode: LeftSidebarMode;
   rightPanel: PanelState;
   blockedOnly: boolean;
   panel: PanelState;
@@ -114,6 +130,7 @@ export function parseUrlState(
   const leftPanel = leftPanelFromUrl ?? defaults.leftPanel;
   const rightPanel = rightPanelFromUrl ?? legacyPanel ?? defaults.rightPanel;
   const panel = rightPanel;
+  const leftSidebarMode = parseLeftSidebarMode(searchParams.get('leftMode'));
 
   const blockedOnly = isBlockedEnabled(searchParams.get('blocked'));
 
@@ -127,7 +144,7 @@ export function parseUrlState(
     ? (graphTabParam as GraphTabType)
     : DEFAULT_GRAPH_TAB;
 
-  return { view, taskId, swarmId, agentId, epicId, leftPanel, rightPanel, blockedOnly, panel, drawer, graphTab };
+  return { view, taskId, swarmId, agentId, epicId, leftPanel, leftSidebarMode, rightPanel, blockedOnly, panel, drawer, graphTab };
 }
 
 export function buildUrlParams(
@@ -190,6 +207,14 @@ export function useUrlState(): UrlState {
     setLeftPanel(state.leftPanel === 'open' ? 'closed' : 'open');
   }, [setLeftPanel, state.leftPanel]);
 
+  const setLeftSidebarMode = useCallback((mode: LeftSidebarMode) => {
+    updateUrl({ leftMode: mode });
+  }, [updateUrl]);
+
+  const toggleLeftSidebarMode = useCallback(() => {
+    setLeftSidebarMode(state.leftSidebarMode === 'epics' ? 'orchestrator' : 'epics');
+  }, [setLeftSidebarMode, state.leftSidebarMode]);
+
   const setRightPanel = useCallback((next: PanelState) => {
     // Keep legacy `panel` in sync while migrating to explicit `right`.
     updateUrl({ right: next, panel: next });
@@ -259,6 +284,9 @@ export function useUrlState(): UrlState {
     leftPanel: state.leftPanel,
     setLeftPanel,
     toggleLeftPanel,
+    leftSidebarMode: state.leftSidebarMode,
+    setLeftSidebarMode,
+    toggleLeftSidebarMode,
     rightPanel: state.rightPanel,
     setRightPanel,
     toggleRightPanel,