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/tests/paths.spec.ts

@@ -1,10 +1,11 @@
 import { homedir } from 'node:os'
-import { join } from 'node:path'
+import { join, resolve } from 'node:path'
 import { describe, expect, it } from 'vitest'
 import {
   DEFAULT_DSH_HOME_DISPLAY,
   DSH_HOME_DIR_NAME,
   defaultDshHome,
+  dshHomeDisplay,
   expandHomePath,
   resolveDshHome,
 } from '@deepseek-ai/dsh-paths'
@@ -24,11 +25,16 @@ describe('dsh path helpers', () => {
     expect(expandHomePath('~other/.dsh')).toBe('~other/.dsh')
   })
 
-  it('resolves explicit DSH home before environment and default locations', () => {
+  it('resolves explicit path before DSH_HOME and the default', () => {
     const envHome = join(homedir(), 'env-dsh')
 
-    expect(resolveDshHome(undefined, { DSH_HOME: '~/env-dsh' })).toBe(envHome)
     expect(resolveDshHome('/tmp/explicit-dsh', { DSH_HOME: '~/env-dsh' })).toBe('/tmp/explicit-dsh')
+    expect(resolveDshHome(undefined, { DSH_HOME: '~/env-dsh' })).toBe(envHome)
     expect(resolveDshHome(undefined, {})).toBe(defaultDshHome())
   })
+
+  it('labels a resolved home by whether it is the default root', () => {
+    expect(dshHomeDisplay(resolve(defaultDshHome()))).toBe('~/.dsh')
+    expect(dshHomeDisplay('/some/other/root')).toBe('$DSH_HOME')
+  })
 })