feat(host): adaptive directory-picker default via -auto chooser

Add @deepseek-ai/dsh-host-directory-picker-auto, a node-half-only chooser
that samples the host situation once at boot (bind host via a new
httpServer.host getter, SSH markers, platform, DISPLAY/WAYLAND_DISPLAY)
and mounts the matching dual-face backend (-native or -browse) as a real
Loader entry in the in-memory root tree; the effect disposer removes it.
Entry-level mounting keeps the seam's one-row-swaps-both-faces invariant:
the client module table discovers the mounted backend's browser half
exactly as a config row's. apps/cli now composes -auto as its
directory-picker row; composing a backend row directly remains the pin.

pnpm-lock.yaml

@@ -230,6 +230,9 @@ importers:
       '@deepseek-ai/dsh-host-apiproxy':
         specifier: workspace:^
         version: link:../../packages/host/apiproxy
+      '@deepseek-ai/dsh-host-directory-picker-auto':
+        specifier: workspace:^
+        version: link:../../packages/host/directory-picker-auto
       '@deepseek-ai/dsh-host-directory-picker-browse':
         specifier: workspace:^
         version: link:../../packages/host/directory-picker-browse
@@ -2934,6 +2937,33 @@ importers:
         specifier: ^4.0.0-rc.7
         version: 4.0.0-rc.7(@cordisjs/plugin-include@1.0.4)(@cordisjs/plugin-loader@1.0.0-rc.5)
 
+  packages/host/directory-picker-auto:
+    devDependencies:
+      '@cordisjs/plugin-include':
+        specifier: workspace:^
+        version: link:../../../vendor/include
+      '@cordisjs/plugin-loader':
+        specifier: workspace:^
+        version: link:../../../vendor/loader
+      '@deepseek-ai/dsh-host-directory-picker':
+        specifier: workspace:^
+        version: link:../directory-picker
+      '@deepseek-ai/dsh-host-directory-picker-browse':
+        specifier: workspace:^
+        version: link:../directory-picker-browse
+      '@deepseek-ai/dsh-host-directory-picker-native':
+        specifier: workspace:^
+        version: link:../directory-picker-native
+      '@deepseek-ai/dsh-host-webserver':
+        specifier: workspace:^
+        version: link:../webserver
+      '@deepseek-ai/dsh-invariants':
+        specifier: workspace:^
+        version: link:../../support/invariants
+      cordis:
+        specifier: ^4.0.0-rc.7
+        version: 4.0.0-rc.7(@cordisjs/plugin-include@vendor+include)(@cordisjs/plugin-loader@vendor+loader)
+
   packages/host/directory-picker-browse:
     dependencies:
       '@deepseek-ai/dsh-host-directory-picker':