ui(onboarding): flat tab navigation + fix vertical-stacked button text

Onboarding was a 7-step linear wizard, same information hierarchy as
Settings but behaving like a modal. Replace with the SettingsShell tab
pattern: one row of six tabs (nodecheck / providers / company /
modelpool / executionmode / mission), free navigation, per-tab
completion ticks derived from the wizard's own validation rules.

Sub-fixes on the same pass:
- ActionButton: add whitespace-nowrap + shrink-0 so "选择" never
  stacks vertically on narrow containers. Global — every caller gets
  the correct behavior
- CompanyStep: CEO Runtime Provider/Model go vertical (space-y-3
  instead of grid-cols-2) so long names like "Fireworks AI" /
  "Kimi K2.5 Turbo Preview 0911" stay readable; workspace-path Input
  wrapped in min-w-0 flex-1 container so it yields, not the button
- MarkdownBody: render react-markdown in chat bubbles (was plain text)

i18n: added onboarding.stepsAria for the tablist label.

src/renderer/components/execution/ModelManagementShared.tsx

@@ -30,7 +30,7 @@ export function StatusBadge({ status }: { status: ConnectorStatus }) {
   const t = useT();
   if (status === "ready") {
     return (
-      <span className="inline-flex items-center gap-1.5 rounded-full bg-success-muted px-2 py-0.5 text-[11px] font-medium text-success">
+      <span className="inline-flex shrink-0 items-center gap-1.5 whitespace-nowrap rounded-full bg-success-muted px-2 py-0.5 text-[11px] font-medium text-success">
         <span className="h-1.5 w-1.5 rounded-full bg-success" />
         {t("models.ready")}
       </span>
@@ -38,7 +38,7 @@ export function StatusBadge({ status }: { status: ConnectorStatus }) {
   }
   if (status === "not_installed") {
     return (
-      <span className="inline-flex items-center gap-1.5 rounded-full bg-muted px-2 py-0.5 text-[11px] font-medium text-muted-foreground">
+      <span className="inline-flex shrink-0 items-center gap-1.5 whitespace-nowrap rounded-full bg-muted px-2 py-0.5 text-[11px] font-medium text-muted-foreground">
         <span className="h-1.5 w-1.5 rounded-full bg-muted-foreground" />
         {t("models.notInstalled")}
       </span>
@@ -46,7 +46,7 @@ export function StatusBadge({ status }: { status: ConnectorStatus }) {
   }
   if (status === "auth_required") {
     return (
-      <span className="inline-flex items-center gap-1.5 rounded-full bg-warning-muted px-2 py-0.5 text-[11px] font-medium text-warning">
+      <span className="inline-flex shrink-0 items-center gap-1.5 whitespace-nowrap rounded-full bg-warning-muted px-2 py-0.5 text-[11px] font-medium text-warning">
         <span className="h-1.5 w-1.5 rounded-full bg-warning" />
         {t("models.authRequired")}
       </span>
@@ -54,14 +54,14 @@ export function StatusBadge({ status }: { status: ConnectorStatus }) {
   }
   if (status === "detected" || (status as string) === "checking") {
     return (
-      <span className="inline-flex items-center gap-1.5 rounded-full bg-muted px-2 py-0.5 text-[11px] font-medium text-muted-foreground">
+      <span className="inline-flex shrink-0 items-center gap-1.5 whitespace-nowrap rounded-full bg-muted px-2 py-0.5 text-[11px] font-medium text-muted-foreground">
         <span className="h-3 w-3 animate-spin rounded-full border-[1.5px] border-muted-foreground border-t-primary" />
         {t("models.checking")}
       </span>
     );
   }
   return (
-    <span className="inline-flex items-center gap-1.5 rounded-full bg-caution-muted px-2 py-0.5 text-[11px] font-medium text-caution">
+    <span className="inline-flex shrink-0 items-center gap-1.5 whitespace-nowrap rounded-full bg-caution-muted px-2 py-0.5 text-[11px] font-medium text-caution">
       <span className="h-1.5 w-1.5 rounded-full bg-caution" />
       {status.replaceAll("_", " ")}
     </span>
@@ -153,12 +153,8 @@ export function ModelToggleList({
       </div>
     );
   }
-  const enabledCount = models.filter((m) => m.enabled).length;
   return (
     <div>
-      <div className="mb-1.5 text-[12px] font-medium text-muted-foreground">
-        {t("models.label")} ({t("models.enabledCount").replace("{enabled}", String(enabledCount)).replace("{total}", String(models.length))})
-      </div>
       <div className="space-y-1">
         {models.map((m) => (
           <div

src/renderer/components/execution/TaskComments.tsx

@@ -5,6 +5,7 @@ import { useT } from "../../i18n"
 import { formatTime } from "../../lib/formatters"
 import { unwrap } from "../../lib/desktop"
 import { ActionButton, InlineNotice } from "../ui"
+import { MarkdownBody } from "../ui/MarkdownBody"
 import { describeActionError } from "./execution-utils"
 
 export function TaskComments({ taskId, companyId, agents, comments, onRefresh }: {
@@ -44,7 +45,9 @@ export function TaskComments({ taskId, companyId, agents, comments, onRefresh }:
                   {agent && <span className="text-[10px] text-muted-foreground">{agent.role}</span>}
                   <span className="text-[10px] text-muted-foreground">{formatTime(comment.createdAt)}</span>
                 </div>
-                <div className="mt-1 whitespace-pre-wrap text-[13px] text-foreground">{comment.body}</div>
+                <div className="mt-1 text-[13px] text-foreground">
+                  <MarkdownBody body={comment.body} />
+                </div>
               </div>
             )
           })}