refactor(picker): split the directory-picker faces into their own packages

The browse and native backends were dual-face packages: a Node backend plus a
browser surface under one tsconfig that referenced Client packages. That put
Client projects — and through them the Client runtime — inside the Host
compiler aggregate, which builds before the generated Remote contributions
exist. Each browser half moves to its own Client package, and both backends
become Node-only.

The interaction is still one choice: the adaptive chooser mounts the backend
and its surface as a pair of Loader entries and tears both down in reverse, so
a resolved kind still swaps both faces. Compositions that pin an interaction
directly now pin the pair, and the chooser's runtime-string package list keeps
naming everything a composing app must resolve.

packages/host/directory-picker-native/tsdown.config.ts

@@ -1,23 +1,31 @@
-import { clientBundle } from '../../client/tsdown.client.ts'
+import { defineConfig } from 'tsdown'
 
-// The Win32 dialog worker builds as its own CJS entry (mirroring
-// dsh-workflow-workerthread's worker): path-loaded by the driver, inlining
-// the dialog logic while koffi stays an external native require.
-export default clientBundle(
-  '@deepseek-ai/dsh-host-directory-picker-native',
-  ['lib/types/index.js', 'lib/types/invariant.js'],
+/**
+ * Node-only backend. The Win32 dialog worker builds as its own CJS entry
+ * (mirroring dsh-workflow-workerthread's worker): path-loaded by the driver,
+ * inlining the dialog logic while koffi stays an external native require.
+ */
+export default defineConfig([
   {
-    companions: [{
-      // The artifact is lib/worker.cjs (the ./worker export the workspace
-      // constraint keys on), bundled from the descriptive source entry.
-      entry: { worker: 'lib/types/win32-dialog-worker.js' },
-      outDir: 'lib',
-      format: ['cjs'],
-      platform: 'node',
-      target: 'es2024',
-      fixedExtension: false,
-      dts: false,
-      clean: false,
-    }],
+    entry: ['lib/types/index.js', 'lib/types/invariant.js'],
+    outDir: 'lib',
+    format: ['esm'],
+    platform: 'node',
+    target: 'es2024',
+    fixedExtension: false,
+    dts: false,
+    clean: false,
   },
-)
+  {
+    // The artifact is lib/worker.cjs (the ./worker export the workspace
+    // constraint keys on), bundled from the descriptive source entry.
+    entry: { worker: 'lib/types/win32-dialog-worker.js' },
+    outDir: 'lib',
+    format: ['cjs'],
+    platform: 'node',
+    target: 'es2024',
+    fixedExtension: false,
+    dts: false,
+    clean: false,
+  },
+])