refactor: consolidate utility functions into shared package

Move duplicate isObject, asString, asNumber, and safeStringify functions from multiple modules into a centralized shared/src/utils.ts module and update imports across cli, server, and web packages. This eliminates code duplication and improves maintainability.

cli/src/agent/backends/acp/AcpMessageHandler.ts

@@ -1,5 +1,6 @@
 import type { AgentMessage, PlanItem } from '@/agent/types';
-import { asString, deriveToolName, isObject } from '@/agent/utils';
+import { asString, isObject } from '@hapi/protocol';
+import { deriveToolName } from '@/agent/utils';
 import { ACP_SESSION_UPDATE_TYPES } from './constants';
 
 function normalizeStatus(status: unknown): 'pending' | 'in_progress' | 'completed' | 'failed' {

cli/src/agent/backends/acp/AcpSdkBackend.ts

@@ -1,5 +1,5 @@
 import type { AgentBackend, AgentMessage, AgentSessionConfig, PermissionRequest, PermissionResponse, PromptContent } from '@/agent/types';
-import { asString, isObject } from '@/agent/utils';
+import { asString, isObject } from '@hapi/protocol';
 import { AcpStdioTransport, type AcpStderrError } from './AcpStdioTransport';
 import { AcpMessageHandler } from './AcpMessageHandler';
 import { logger } from '@/ui/logger';

cli/src/agent/utils.ts

@@ -1,10 +1,4 @@
-export function isObject(value: unknown): value is Record<string, unknown> {
-    return Boolean(value) && typeof value === 'object';
-}
-
-export function asString(value: unknown): string | null {
-    return typeof value === 'string' ? value : null;
-}
+import { isObject } from '@hapi/protocol';
 
 export function deriveToolName(input: {
     title?: string | null;

cli/src/claude/utils/permissionHandler.ts

@@ -15,6 +15,7 @@ import { getToolName } from "./getToolName";
 import { EnhancedMode, PermissionMode } from "../loop";
 import { getToolDescriptor } from "./getToolDescriptor";
 import { delay } from "@/utils/time";
+import { isObject } from "@hapi/protocol";
 import {
     BasePermissionHandler,
     type PendingPermissionRequest,
@@ -33,10 +34,6 @@ interface PermissionResponse {
 
 const PLAN_EXIT_MODES: PermissionMode[] = ['default', 'acceptEdits', 'bypassPermissions'];
 
-function isObject(value: unknown): value is Record<string, unknown> {
-    return Boolean(value) && typeof value === 'object';
-}
-
 function isAskUserQuestionToolName(toolName: string): boolean {
     return toolName === 'AskUserQuestion' || toolName === 'ask_user_question';
 }

cli/src/codex/codexMcpClient.ts

@@ -4,6 +4,7 @@
 
 import { Client } from '@modelcontextprotocol/sdk/client/index.js';
 import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js';
+import { isObject } from '@hapi/protocol';
 import { logger } from '@/ui/logger';
 import { isProcessAlive, killProcess } from '@/utils/process';
 import type { CodexSessionConfig, CodexToolResponse } from './types';
@@ -20,10 +21,6 @@ type ElicitRequestedSchema = {
     required?: string[];
 };
 
-function isObject(value: unknown): value is Record<string, unknown> {
-    return Boolean(value) && typeof value === 'object';
-}
-
 function extractRequestedSchema(params: Record<string, unknown>): ElicitRequestedSchema | null {
     const raw = params.requestedSchema;
     if (!isObject(raw)) return null;