feat(pool): an admin's switch moves a user's Claude login at once

PUT /api/accounts/pins (and agenthub accounts pin) now writes a pinned
Claude login into the user's home right away (claude-pool.switchHome):
every home's newer pair is copied back first, the member's own login is
never written over, and no pane is restarted — running sessions take the
new pair at their next credentials read. A live home stays on the login it
holds, so unpinning does not flip it back. The Users page calls it
"Switch a user's account" and says what happened.

client/src/components/users/AccountPoolCard.tsx

@@ -8,8 +8,9 @@
  * `.credentials.json`, or a `claude setup-token` token; for Codex an OpenAI
  * API key or a pasted `auth.json` — or removes one, each time with their own
  * password again; an analyst only reads. The secret only goes IN: the server
- * never sends it back. An admin can also pin a user to one account
- * (`PUT /api/accounts/pins`): that user's new sessions skip the balancer.
+ * never sends it back. An admin can also switch a user to one account
+ * (`PUT /api/accounts/pins`): that user's sessions skip the balancer, and a
+ * Claude login goes into their home at once — no restart.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
 
@@ -291,11 +292,14 @@ export function AccountPoolCard({ isAdmin }: { isAdmin: boolean }) {
           pool={pool}
           initial={pinning}
           onClose={() => setPinning(null)}
-          onDone={(user, account) => {
-            toast.success(
-              account
-                ? t("pool.pinDone.pinned", { user, account })
-                : t("pool.pinDone.unpinned", { user })
+          onDone={(user, account, switched) => {
+            const key = !account
+              ? "unpinned"
+              : switched === "switched" || switched === "own-login" || switched === "expired"
+                ? switched
+                : "pinned";
+            (key === "own-login" || key === "expired" ? toast.info : toast.success)(
+              t(`pool.pinDone.${key}`, { user, account })
             );
             setPinning(null);
             void load();
@@ -307,8 +311,8 @@ export function AccountPoolCard({ isAdmin }: { isAdmin: boolean }) {
 }
 
 /**
- * Pin a user to one account of a tool, or unpin them ("None"). Opened on an
- * existing pin it starts on that user with "None", so one click unpins.
+ * Switch a user to one account of a tool, or back to automatic. Opened on an
+ * existing pin it starts on that user with "Automatic", so one click unpins.
  */
 function PinUserDialog({
   pool,
@@ -319,7 +323,7 @@ function PinUserDialog({
   pool: AccountPool;
   initial: { tool: PoolTool; userId?: number };
   onClose: () => void;
-  onDone: (user: string, account: string | null) => void;
+  onDone: (user: string, account: string | null, switched: string | null) => void;
 }) {
   const { t } = useTranslation("users");
   const [tool, setTool] = useState<PoolTool>(initial.tool);
@@ -348,7 +352,7 @@ function PinUserDialog({
     setError(null);
     try {
       const r = await api.accountPool.pin(tool, userId, account || null, current);
-      onDone(r.pin.username, r.pin.account);
+      onDone(r.pin.username, r.pin.account, r.switched ?? null);
     } catch (e) {
       setError(errorText(t, e));
     } finally {

client/src/components/users/__tests__/AccountPoolCard.test.tsx

@@ -5,8 +5,8 @@
  * admin adds an account only with their own password typed (the token goes
  * in once and is not shown back) — a saved login moved in (the server's own
  * included), or a setup-token — and removes one the same way, and an analyst
- * sees no add or remove control. An admin pins a user to one account and
- * unpins them, each with their own password; the pins show on the accounts.
+ * sees no add or remove control. An admin switches a user to one account and
+ * back to automatic, each with their own password; it shows on the accounts.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
 
@@ -173,17 +173,20 @@ describe("AccountPoolCard", () => {
       ...POOL,
       pins: { claude: [{ userId: 8, username: "leo", account: "team-1" }], codex: [] },
     });
-    accountPool.pin.mockResolvedValue({ pin: { userId: 7, username: "mia", account: "team-1" } });
+    accountPool.pin.mockResolvedValue({
+      pin: { userId: 7, username: "mia", account: "team-1" },
+      switched: "switched",
+    });
     const user = userEvent.setup();
     render(<AccountPoolCard isAdmin />);
-    expect(await screen.findByText("Pinned: leo")).toBeInTheDocument();
-    await user.click(screen.getByRole("button", { name: /pin a user/i }));
+    expect(await screen.findByText("Used by: leo")).toBeInTheDocument();
+    await user.click(screen.getByRole("button", { name: /switch a user's account/i }));
     const dialog = await screen.findByRole("dialog");
     await waitFor(() => expect(screen.getByRole("option", { name: "mia" })).toBeInTheDocument());
     await user.selectOptions(screen.getByLabelText("User"), "7");
     await user.selectOptions(screen.getByLabelText("Account"), "team-1");
     const confirm = Array.from(dialog.querySelectorAll("button")).find(
-      (b) => b.textContent === "Save pin"
+      (b) => b.textContent === "Switch"
     )!;
     expect(confirm).toBeDisabled();
     await user.type(screen.getByLabelText("Your password"), "boss-pass");
@@ -198,14 +201,17 @@ describe("AccountPoolCard", () => {
       ...POOL,
       pins: { claude: [{ userId: 8, username: "leo", account: "team-1" }], codex: [] },
     });
-    accountPool.pin.mockResolvedValue({ pin: { userId: 8, username: "leo", account: null } });
+    accountPool.pin.mockResolvedValue({
+      pin: { userId: 8, username: "leo", account: null },
+      switched: null,
+    });
     const user = userEvent.setup();
     render(<AccountPoolCard isAdmin />);
-    await user.click(await screen.findByRole("button", { name: "Unpin leo" }));
+    await user.click(await screen.findByRole("button", { name: "Back to automatic for leo" }));
     const dialog = await screen.findByRole("dialog");
     await user.type(screen.getByLabelText("Your password"), "boss-pass");
     await user.click(
-      Array.from(dialog.querySelectorAll("button")).find((b) => b.textContent === "Save pin")!
+      Array.from(dialog.querySelectorAll("button")).find((b) => b.textContent === "Switch")!
     );
     await waitFor(() =>
       expect(accountPool.pin).toHaveBeenCalledWith("claude", 8, null, "boss-pass")