Add the settings card — the browser half

The settings namespace was registered but nothing drew a form for it, because
the Plugin configuration tab renders the INTERSECTION of the namespaces the Host
serves and the cards a browser half claims. A served namespace with no card
renders nothing at all. This is the missing card.

Plain ESM in the module-loader wrapper, no build step, requiring only `react` —
which is in the platform seed table. Anything outside that table would have to be
bundled into this file or declared in `dsh.client.external`, and the tests fail
loudly on any other specifier.

It stages edits and writes them on Save; a cleared field is an `unset` rather
than a write of "", so the value re-inherits the composition layer instead of
becoming empty, and the user layer's presence is what marks a field overridden.
Reset clears every override. A namespace this client cannot reach renders
nothing, so a deployment without the Host half shows no trace.

package.json gains an `exports` map (the loader reads `exports["./client"]`; a
bare `main` would not be enough) and the `dsh.client` declaration.

package.json

@@ -3,11 +3,22 @@
   "version": "0.1.0",
   "private": true,
   "type": "module",
-  "description": "Slopo as a DeepSeek Harness bundle — embedding-based duplicate-code review, exposed as three user-triggered skills and one config-aware tool.",
+  "description": "Slopo as a DeepSeek Harness bundle — embedding-based duplicate-code review, exposed as three user-triggered skills, one config-aware tool, and a settings card.",
   "main": "index.js",
+  "exports": {
+    ".": {
+      "default": "./index.js"
+    },
+    "./client": {
+      "default": "./client/client.js"
+    },
+    "./cordis.patch.yml": "./cordis.patch.yml",
+    "./package.json": "./package.json"
+  },
   "files": [
     "index.js",
     "lib",
+    "client",
     "skills",
     "cordis.patch.yml",
     "README.md",
@@ -23,6 +34,13 @@
   "dsh": {
     "bundle": {
       "patch": "./cordis.patch.yml"
+    },
+    "client": {
+      "platform": "web",
+      "inject": [
+        "@deepseek-ai/dsh-client-ui-slots",
+        "@deepseek-ai/dsh-client-ui-settings"
+      ]
     }
   },
   "keywords": [