feat(KB-036): add worktreeNaming setting for configurable worktree directory names

- Add worktreeNaming setting type with 'random' | 'task-id' | 'task-title' options
- Update executor to generate worktree names based on setting value
- Create worktree-names.ts utility module with generateWorktreeName function
- Add comprehensive executor tests for all naming strategies
- Update AGENTS.md documentation with setting description and usage
- Include changeset for patch release

packages/engine/src/worktree-names.ts

@@ -28,6 +28,23 @@ export const NOUNS = [
   "thorn", "tiger", "trail", "trout", "wren",
 ];
 
+/**
+ * Convert a string to a URL-friendly slug.
+ *
+ * - Lowercase
+ * - Replace spaces, underscores, and special chars with hyphens
+ * - Collapse multiple hyphens
+ * - Trim leading/trailing hyphens
+ */
+export function slugify(str: string): string {
+  return str
+    .toLowerCase()
+    .replace(/[^a-z0-9\s-]/g, "") // Remove special characters except spaces and hyphens
+    .replace(/\s+/g, "-") // Replace spaces with hyphens
+    .replace(/-+/g, "-") // Collapse multiple hyphens
+    .replace(/^-|-$/g, ""); // Trim leading/trailing hyphens
+}
+
 /**
  * Generate a random, human-friendly worktree directory name.
  *