Merge origin/master: session projection base, command channel, composer seats

Resolution follows the reattachment plan: the #587 wire layer (planMode/
setPlanMode RPC, prompt.planMode, client Session projection fences) is
dropped in favor of the session-projection base now on master; master
structure wins in all shared files. Kept from the PR side: the approval-only
pending filter in ChatView (questions render solely through the composer
takeover) and the auto-merged QuestionComposer improvements. The deleted
host/runtime package and retired test carriers are removed with master.

tsconfig.client.json

@@ -14,6 +14,9 @@
     "types": ["node"]
   },
   "include": [
+    // Source-subpath test imports can arrive through workspace links whose
+    // realpath semantics vary by host. Load package CSS declarations directly.
+    "packages/client/*/src/css-modules.d.ts",
     "packages/client/*/tests/**/*.ts",
     "packages/client/*/tests/**/*.tsx",
     "packages/client/tsdown.client.ts",
@@ -34,11 +37,20 @@
     { "path": "./packages/client/ui-layout" },
     { "path": "./packages/client/ui-sidebar" },
     { "path": "./packages/client/ui-conversation" },
+    { "path": "./packages/client/ui-workspace" },
+    { "path": "./packages/client/ui-slash" },
+    { "path": "./packages/client/ui-command" },
+    { "path": "./packages/client/ui-skill" },
+    { "path": "./packages/client/ui-subagent" },
+    { "path": "./packages/client/ui-model" },
     { "path": "./packages/client/ui-plan" },
     { "path": "./packages/client/ui-question" },
     { "path": "./packages/client/ui-trajectory" },
     { "path": "./packages/client/ui-theme" },
-    { "path": "./packages/client/i18n" },
+    { "path": "./packages/client/ui-settings" },
+    { "path": "./packages/client/ui-settings-general" },
+    { "path": "./packages/client/ui-models" },
+    { "path": "./packages/client/locale" },
     { "path": "./packages/client/web" },
     { "path": "./apps/web" }
   ]