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/lib/pi-runtime-detection.ts

@@ -0,0 +1,103 @@
+import fs from 'node:fs/promises';
+import os from 'node:os';
+import path from 'node:path';
+import { getRuntimePaths } from './runtime-manager';
+
+export type PiRuntimeMode = 'linked-pi' | 'bb-managed-pi';
+export type PiInstallState = 'ready' | 'bootstrap-required';
+
+export interface PiRuntimeResolution {
+  mode: PiRuntimeMode;
+  installState: PiInstallState;
+  sdkPath: string | null;
+  authPath: string | null;
+  agentDir: string;
+  version: string;
+  managedRoot: string;
+  reason: string;
+}
+
+async function pathExists(target: string): Promise<boolean> {
+  try {
+    await fs.access(target);
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+export function getManagedPiPaths(version: string, home: string = os.homedir()) {
+  const runtime = getRuntimePaths(home, version);
+  const managedRoot = path.join(runtime.runtimeRoot, 'pi');
+  return {
+    managedRoot,
+    sdkPath: path.join(managedRoot, 'node_modules', '@mariozechner', 'pi-coding-agent', 'dist', 'index.js'),
+    agentDir: path.join(managedRoot, 'agent'),
+    authPath: path.join(managedRoot, 'agent', 'auth.json'),
+  };
+}
+
+export async function detectPiRuntimeStrategy(params: {
+  cwd?: string;
+  version?: string;
+  home?: string;
+  globalPiRoot?: string;
+  allowLinkedPi?: boolean;
+} = {}): Promise<PiRuntimeResolution> {
+  const cwd = params.cwd ?? process.cwd();
+  const version = params.version ?? '0.1.0';
+  const home = params.home ?? os.homedir();
+  const globalPiRoot = params.globalPiRoot ?? '/home/clawdbot/npm-global/lib/node_modules/@mariozechner/pi-coding-agent';
+  const allowLinkedPi = params.allowLinkedPi ?? false;
+
+  const localSdkPath = path.join(cwd, 'node_modules', '@mariozechner', 'pi-coding-agent', 'dist', 'index.js');
+  const globalSdkPath = path.join(globalPiRoot, 'dist', 'index.js');
+  const linkedAuthPath = path.join(home, '.pi', 'agent', 'auth.json');
+  const linkedAgentDir = path.join(home, '.pi', 'agent');
+
+  const managed = getManagedPiPaths(version, home);
+
+  if (allowLinkedPi && await pathExists(localSdkPath)) {
+    return {
+      mode: 'linked-pi',
+      installState: 'ready',
+      sdkPath: localSdkPath,
+      authPath: (await pathExists(linkedAuthPath)) ? linkedAuthPath : null,
+      agentDir: linkedAgentDir,
+      version,
+      managedRoot: managed.managedRoot,
+      reason: 'Using project-local Pi SDK and linked ~/.pi/agent state when available.',
+    };
+  }
+
+  if (allowLinkedPi && await pathExists(globalSdkPath)) {
+    return {
+      mode: 'linked-pi',
+      installState: 'ready',
+      sdkPath: globalSdkPath,
+      authPath: (await pathExists(linkedAuthPath)) ? linkedAuthPath : null,
+      agentDir: linkedAgentDir,
+      version,
+      managedRoot: managed.managedRoot,
+      reason: 'Using globally installed Pi SDK and linked ~/.pi/agent state when available.',
+    };
+  }
+
+  const managedSdkExists = await pathExists(managed.sdkPath);
+  const managedAuthExists = await pathExists(managed.authPath);
+
+  return {
+    mode: 'bb-managed-pi',
+    installState: managedSdkExists ? 'ready' : 'bootstrap-required',
+    sdkPath: managedSdkExists ? managed.sdkPath : null,
+    authPath: managedAuthExists ? managed.authPath : null,
+    agentDir: managed.agentDir,
+    version,
+    managedRoot: managed.managedRoot,
+    reason: managedSdkExists
+      ? 'Using BeadBoard-managed Pi runtime.'
+      : allowLinkedPi
+        ? 'No linked Pi installation found. BeadBoard-managed Pi bootstrap is required.'
+        : 'BeadBoard-managed Pi bootstrap is required.',
+  };
+}