fix: allow runtime image attachment paths

src/attachment-base-dirs.ts

@@ -0,0 +1,21 @@
+import path from 'path';
+
+import { DATA_DIR } from './config.js';
+import { isValidGroupFolder } from './group-folder.js';
+import type { RegisteredGroup } from './types.js';
+
+function unique(values: Array<string | null | undefined>): string[] {
+  return [
+    ...new Set(values.filter((value): value is string => Boolean(value))),
+  ];
+}
+
+export function resolveRuntimeAttachmentBaseDirs(
+  group: RegisteredGroup,
+): string[] | undefined {
+  const workspaceRoot = isValidGroupFolder(group.folder)
+    ? path.resolve(DATA_DIR, 'workspaces', group.folder)
+    : null;
+  const dirs = unique([group.workDir, workspaceRoot]);
+  return dirs.length > 0 ? dirs : undefined;
+}