refactor(paths): collapse harness home resolution into one resolver

Delete @deepseek-ai/dsh-home and make dsh-paths the sole owner of the
single-root harness home ($DSH_HOME || ~/.dsh). Migrate tool-bash,
skill-local, and agent-spine-demo off dsh-home, and fold telemetry's
divergent globalConfigDir onto the shared resolver, dropping its second
XDG/APPDATA policy and the deepseek-harness namespace so the anonymous
id lives under the harness home. Add dshHomeDisplay() for symbolic
user-facing paths, replacing workspace-context's bespoke check.

packages/util/paths/src/index.ts

@@ -36,7 +36,10 @@ export function expandHomePath(path: string): string {
 }
 
 /**
- * Resolve an explicitly configured, environment-selected, or default DSH home.
+ * Resolve the single-root DeepSeek Harness home.
+ *
+ * Precedence, highest first: an explicit configured path, `$DSH_HOME`, then
+ * `~/.dsh`. The harness keeps all user data under one root.
  * @param configured - explicit harness-home override, which has highest precedence.
  * @param env - environment mapping used to read `DSH_HOME`.
  * @returns the normalized absolute harness home path.
@@ -45,3 +48,15 @@ export function resolveDshHome(configured?: string, env: Record<string, string |
   const selected = configured ?? env[DSH_HOME_ENV] ?? defaultDshHome()
   return resolve(expandHomePath(selected))
 }
+
+/**
+ * Describe a resolved harness home symbolically for user-facing display.
+ *
+ * It never returns an absolute machine path: the default home is labelled
+ * `~/.dsh`, and any configured home is labelled `$DSH_HOME`.
+ * @param resolvedHome - the absolute path returned by {@link resolveDshHome}.
+ * @returns `~/.dsh` for the default home, otherwise `$DSH_HOME`.
+ */
+export function dshHomeDisplay(resolvedHome: string): string {
+  return resolvedHome === resolve(defaultDshHome()) ? DEFAULT_DSH_HOME_DISPLAY : `$${DSH_HOME_ENV}`
+}