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/image-handler.ts

@@ -0,0 +1,114 @@
+/**
+ * Image handling utilities for processing image files
+ *
+ * Provides utilities for:
+ * - MIME type detection based on file extensions
+ * - Base64 encoding of image files
+ * - Content block generation for Claude SDK format
+ * - Path resolution (relative/absolute)
+ */
+
+import fs from "fs/promises";
+import path from "path";
+import type { ImageData, ImageContentBlock } from '@automaker/types';
+
+/**
+ * MIME type mapping for image file extensions
+ */
+const IMAGE_MIME_TYPES: Record<string, string> = {
+  ".jpg": "image/jpeg",
+  ".jpeg": "image/jpeg",
+  ".png": "image/png",
+  ".gif": "image/gif",
+  ".webp": "image/webp",
+} as const;
+
+/**
+ * Get MIME type for an image file based on extension
+ *
+ * @param imagePath - Path to the image file
+ * @returns MIME type string (defaults to "image/png" for unknown extensions)
+ */
+export function getMimeTypeForImage(imagePath: string): string {
+  const ext = path.extname(imagePath).toLowerCase();
+  return IMAGE_MIME_TYPES[ext] || "image/png";
+}
+
+/**
+ * Read an image file and convert to base64 with metadata
+ *
+ * @param imagePath - Path to the image file
+ * @returns Promise resolving to image data with base64 encoding
+ * @throws Error if file cannot be read
+ */
+export async function readImageAsBase64(imagePath: string): Promise<ImageData> {
+  const imageBuffer = await fs.readFile(imagePath);
+  const base64Data = imageBuffer.toString("base64");
+  const mimeType = getMimeTypeForImage(imagePath);
+
+  return {
+    base64: base64Data,
+    mimeType,
+    filename: path.basename(imagePath),
+    originalPath: imagePath,
+  };
+}
+
+/**
+ * Convert image paths to content blocks (Claude SDK format)
+ * Handles both relative and absolute paths
+ *
+ * @param imagePaths - Array of image file paths
+ * @param workDir - Optional working directory for resolving relative paths
+ * @returns Promise resolving to array of image content blocks
+ */
+export async function convertImagesToContentBlocks(
+  imagePaths: string[],
+  workDir?: string
+): Promise<ImageContentBlock[]> {
+  const blocks: ImageContentBlock[] = [];
+
+  for (const imagePath of imagePaths) {
+    try {
+      // Resolve to absolute path if needed
+      const absolutePath = workDir && !path.isAbsolute(imagePath)
+        ? path.join(workDir, imagePath)
+        : imagePath;
+
+      const imageData = await readImageAsBase64(absolutePath);
+
+      blocks.push({
+        type: "image",
+        source: {
+          type: "base64",
+          media_type: imageData.mimeType,
+          data: imageData.base64,
+        },
+      });
+    } catch (error) {
+      console.error(`[ImageHandler] Failed to load image ${imagePath}:`, error);
+      // Continue processing other images
+    }
+  }
+
+  return blocks;
+}
+
+/**
+ * Build a list of image paths for text prompts
+ * Formats image paths as a bulleted list for inclusion in text prompts
+ *
+ * @param imagePaths - Array of image file paths
+ * @returns Formatted string with image paths, or empty string if no images
+ */
+export function formatImagePathsForPrompt(imagePaths: string[]): string {
+  if (imagePaths.length === 0) {
+    return "";
+  }
+
+  let text = "\n\nAttached images:\n";
+  for (const imagePath of imagePaths) {
+    text += `- ${imagePath}\n`;
+  }
+  return text;
+}