feat: ship the ssh terminal as a first-party in-process plugin

Adds a hardcoded process:transport-owner tier so the terminal can own its
WebSocket server and ssh2 clients, which cannot cross the worker boundary.

src/ui/sidebar/AdminPluginsSection.tsx

@@ -0,0 +1,96 @@
+import { useCallback, useEffect, useState } from "react";
+import { useTranslation } from "react-i18next";
+import { Puzzle } from "lucide-react";
+import { toast } from "sonner";
+import { SettingRow } from "@/components/section-card";
+import {
+  getPlugins,
+  setPluginEnabled,
+  type PluginSummary,
+} from "@/api/plugins-api";
+import { refreshPluginState } from "@/shell/pluginLoader";
+import { AccordionSection, AdminToggle } from "./AdminSettingsShared";
+
+export function AdminPluginsSection({
+  open,
+  onToggle,
+}: {
+  open: boolean;
+  onToggle: () => void;
+}) {
+  const { t } = useTranslation();
+  const [plugins, setPlugins] = useState<PluginSummary[]>([]);
+  const [busy, setBusy] = useState<string | null>(null);
+  const [loaded, setLoaded] = useState(false);
+
+  const load = useCallback(async () => {
+    try {
+      setPlugins(await getPlugins());
+    } catch {
+      toast.error(t("admin.pluginsLoadFailed"));
+    } finally {
+      setLoaded(true);
+    }
+  }, [t]);
+
+  useEffect(() => {
+    if (open && !loaded) void load();
+  }, [open, loaded, load]);
+
+  const toggle = async (plugin: PluginSummary) => {
+    setBusy(plugin.id);
+    try {
+      await setPluginEnabled(plugin.id, !plugin.enabled);
+      await load();
+      // Re-read state so the shell picks the change up without a reload.
+      await refreshPluginState();
+      toast.success(
+        plugin.enabled
+          ? t("admin.pluginDisabled", { name: plugin.name })
+          : t("admin.pluginEnabled", { name: plugin.name }),
+      );
+    } catch {
+      toast.error(t("admin.pluginToggleFailed"));
+    } finally {
+      setBusy(null);
+    }
+  };
+
+  return (
+    <AccordionSection
+      label={t("admin.plugins")}
+      icon={<Puzzle className="size-3.5" />}
+      open={open}
+      onToggle={onToggle}
+    >
+      {plugins.length === 0 ? (
+        <p className="text-xs text-muted-foreground py-3">
+          {loaded ? t("admin.pluginsNone") : t("common.loading")}
+        </p>
+      ) : (
+        plugins.map((plugin) => (
+          <SettingRow
+            key={plugin.id}
+            label={plugin.name}
+            badge={
+              plugin.tier === "first-party"
+                ? t("admin.pluginBuiltIn")
+                : undefined
+            }
+            description={
+              plugin.lastError
+                ? plugin.lastError
+                : `v${plugin.version} · ${plugin.runtimeState}`
+            }
+          >
+            <AdminToggle
+              on={plugin.enabled}
+              onToggle={() => void toggle(plugin)}
+              disabled={busy === plugin.id}
+            />
+          </SettingRow>
+        ))
+      )}
+    </AccordionSection>
+  );
+}