feat(host,client): compose directory picking through slots — dual-face -native, no wire advertisement

ui-workspace's two trigger surfaces each declare a single-kind directory-flow
hole (conversation.hero.workspace.directoryFlow / sidebar.workspaces.directoryFlow,
same owner contract) and keep only the trigger and the adoption: the Open-local-
folder entry renders while the surface's hole is occupied, and the occupant
reports one picked path per open through the hole's owner conversation
(open/busy/onPicked/onCancel/onError).

directory-picker-native becomes dual-face: its browser half fills both holes
with a renderless occupant driving host.pickDirectory, so the cordis.yml row
that mounts the backend also composes the client interaction — a mismatch is
impossible and a second flow package fails at client load.

With composition wiring both sides, the host.describe.directoryPicker
advertisement and the client's kind branching lose their last consumer:
the field, WorkspacesService.directoryPickerKind(), the DirectoryPickerKind
wire type, and the picker's per-open describe read are deleted. The connection
fixture now serves a deterministic pickDirectory path so the keyless snapshot
drives the full pick-then-adopt flow. ui-workspace's hand-rolled declaration
deferral is replaced by the deferRegistration helper it duplicated.

packages/host/directory-picker-native/tsconfig.json

@@ -1,19 +1,16 @@
 {
-  "extends": "../../../tsconfig.base.json",
+  "extends": "../../../tsconfig.base.client.json",
   "compilerOptions": {
     "rootDir": "src",
-    "outDir": "lib/types"
+    "outDir": "lib/types",
+    "types": [
+      "node"
+    ]
   },
   "include": [
     "src"
   ],
   "references": [
-    {
-      "path": "../../../vendor/cosmokit"
-    },
-    {
-      "path": "../../../vendor/cordis"
-    },
     {
       "path": "../directory-picker"
     },
@@ -22,6 +19,15 @@
     },
     {
       "path": "../../util/native-command"
+    },
+    {
+      "path": "../../client/ui-slots"
+    },
+    {
+      "path": "../../client/runtime"
+    },
+    {
+      "path": "../../client/ui-workspace"
     }
   ]
 }