feat(tools): add barrel exports and allBuiltinTools list

src/tools/index.ts

@@ -0,0 +1,12 @@
+export type { Tool, ToolCall, ToolResult, ToolInputSchema, ToolUseBlock, ToolResultBlock, ToolUseMessage, ToolResultMessage } from './types.js';
+export { ToolRegistry } from './registry.js';
+export type { AnthropicToolDef, OpenAIToolDef } from './registry.js';
+export { ToolExecutor } from './executor.js';
+export type { ToolExecutorConfig } from './executor.js';
+export { allBuiltinTools } from './builtin/index.js';
+export { shellExecTool } from './builtin/shell.js';
+export { fileReadTool } from './builtin/file-read.js';
+export { fileWriteTool } from './builtin/file-write.js';
+export { fileEditTool } from './builtin/file-edit.js';
+export { fileListTool } from './builtin/file-list.js';
+export { webFetchTool } from './builtin/web-fetch.js';