feat: add @automaker/utils package

- Extract error handling utilities (isAbortError, classifyError, etc.)
- Extract conversation utilities (formatHistoryAsText, etc.)
- Extract image handling utilities (readImageAsBase64, etc.)
- Extract prompt building utilities (buildPromptWithImages)
- Extract logger utilities (createLogger, setLogLevel)
- Extract file system utilities (mkdirSafe, existsSafe)

All utilities now use @automaker/types for type imports.
Provides shared utility functions for both server and UI.

Dependencies: @automaker/types

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

libs/utils/src/index.ts

@@ -0,0 +1,50 @@
+/**
+ * @automaker/utils
+ * Shared utility functions for AutoMaker
+ */
+
+// Error handling
+export {
+  isAbortError,
+  isCancellationError,
+  isAuthenticationError,
+  classifyError,
+  getUserFriendlyErrorMessage,
+} from './error-handler';
+
+// Conversation utilities
+export {
+  extractTextFromContent,
+  normalizeContentBlocks,
+  formatHistoryAsText,
+  convertHistoryToMessages,
+} from './conversation-utils';
+
+// Image handling
+export {
+  getMimeTypeForImage,
+  readImageAsBase64,
+  convertImagesToContentBlocks,
+  formatImagePathsForPrompt,
+} from './image-handler';
+
+// Prompt building
+export {
+  buildPromptWithImages,
+  type PromptContent,
+  type PromptWithImages,
+} from './prompt-builder';
+
+// Logger
+export {
+  createLogger,
+  getLogLevel,
+  setLogLevel,
+  LogLevel,
+} from './logger';
+
+// File system utilities
+export {
+  mkdirSafe,
+  existsSafe,
+} from './fs-utils';