feat(workspace,settings): model menu chip in the composer, compact settings panels

The workspace home's composer takes ONE Model chip (ModelMenu: model list
plus Effort) and moves AI Router / Permission / Local-New worktree into the
row under it; Settings drops the General-page cost card and export row,
PricingSettings and the empty states are compacted for settings panels.

client/src/pages/GitCredentialsConfig.tsx

@@ -10,7 +10,7 @@
  */
 import { useCallback, useEffect, useState } from "react";
 import { useTranslation } from "react-i18next";
-import { KeyRound, Pencil, Plus, Trash2 } from "lucide-react";
+import { Pencil, Plus, Trash2 } from "lucide-react";
 import { api, type GitCredential } from "../lib/api";
 
 const INPUT =
@@ -69,13 +69,8 @@ export function GitCredentialsConfig() {
   return (
     <div className="space-y-4">
       <div className="flex items-start justify-between gap-4">
-        <div>
-          <h2 className="flex items-center gap-2 text-sm font-semibold text-fg-primary">
-            <KeyRound className="h-4 w-4 text-fg-muted" />
-            {t("gitCreds.title")}
-          </h2>
-          <p className="mt-1 max-w-2xl text-xs text-fg-muted">{t("gitCreds.description")}</p>
-        </div>
+        {/* The page header above already names the section. */}
+        <p className="max-w-2xl text-xs text-fg-muted">{t("gitCreds.description")}</p>
         <button
           type="button"
           onClick={() => setForm({ url: "", username: "", token: "" })}