refactor(core): centralize DSH home resolution

packages/util/home/src/index.ts

@@ -0,0 +1,23 @@
+/**
+ * Canonical DeepSeek Harness home-directory resolution.
+ *
+ * @module @deepseek-ai/dsh-home
+ */
+
+import { homedir } from 'node:os'
+import { join, resolve } from 'node:path'
+
+const DEFAULT_DSH_HOME_DIRNAME = '.dsh'
+
+/** Environment variable that overrides the default Harness home directory. */
+export const DSH_HOME_ENV = 'DSH_HOME' as const
+
+/**
+ * Resolve the DeepSeek Harness home directory without caching or mutating the environment.
+ *
+ * @param configured - Optional configured path, which takes precedence over the environment.
+ * @returns The absolute configured path, `$DSH_HOME`, or `~/.dsh`, in that order.
+ */
+export function resolveDshHome(configured?: string): string {
+  return resolve(configured ?? process.env[DSH_HOME_ENV] ?? join(homedir(), DEFAULT_DSH_HOME_DIRNAME))
+}