refactor(gui): features register their own settings surfaces

Settings collaboration direction (recorded in the note): the shell only
provides composition faces — feature plugins register themselves. The
General section moves into the ui-settings shell (order 0, skeleton
rows) and declares the settings.general.item list slot; locale registers
the Language row and ui-theme the Appearance row (each with its own
store mirror, dictionaries, and ledger-judged deferral); the
ui-settings-general package is gone. ui-settings-models becomes
ui-models — a feature package that contributes its Settings section
rather than a settings-owned satellite. The item-slot SlotMap entry is
authored in the ui-settings contract and repeated verbatim in
locale/ui-theme (reference-cycle avoidance; declaration merging keeps
the copies identical).

packages/client/ui-theme/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@deepseek-ai/dsh-client-ui-theme",
-  "description": "Theme plugin: ThemeService (light/dark/system preference, prefers-color-scheme resolution, theme/change snapshots; no DOM), --dsw-* token base stylesheets",
+  "description": "Theme plugin: ThemeService (light/dark/system preference, prefers-color-scheme resolution, theme/change snapshots; no DOM), --dsw-* token base stylesheets; registers the Appearance settings row",
   "version": "0.0.1",
   "private": true,
   "type": "module",
@@ -24,18 +24,32 @@
     "./package.json": "./package.json"
   },
   "dshClient": {
-    "inject": [],
+    "inject": [
+      "@deepseek-ai/dsh-client-runtime",
+      "@deepseek-ai/dsh-client-locale"
+    ],
     "platform": "web",
     "immediately": true
   },
   "license": "BSD-3-Clause",
   "peerDependencies": {
+    "@deepseek-ai/dsh-client-locale": "^0.0.1",
+    "@deepseek-ai/dsh-client-runtime": "^0.0.1",
+    "@deepseek-ai/dsh-client-ui-primitives": "^0.0.1",
+    "@deepseek-ai/dsh-client-ui-slots": "^0.0.1",
     "@deepseek-ai/dsh-invariants": "^0.0.1",
-    "cordis": "^4.0.0-rc.7"
+    "cordis": "^4.0.0-rc.7",
+    "react": "^18.2.0"
   },
   "devDependencies": {
+    "@deepseek-ai/dsh-client-locale": "workspace:^",
+    "@deepseek-ai/dsh-client-runtime": "workspace:^",
+    "@deepseek-ai/dsh-client-ui-primitives": "workspace:^",
+    "@deepseek-ai/dsh-client-ui-slots": "workspace:^",
     "@deepseek-ai/dsh-invariants": "workspace:^",
-    "cordis": "^4.0.0-rc.7"
+    "@types/react": "~18.3.1",
+    "cordis": "^4.0.0-rc.7",
+    "react": "^18.2.0"
   },
   "files": [
     "lib/index.js",
@@ -48,5 +62,8 @@
   "scripts": {
     "bundle": "tsdown",
     "watch": "tsdown --watch"
+  },
+  "dependencies": {
+    "clsx": "^2.0.0"
   }
 }