refactor(claude-desktop): lock route IDs to sonnet/opus/haiku roles

Adapt to Claude Desktop 1.6259.1+ fail-all validation which only
accepts claude-(sonnet|opus|haiku)-* route IDs. Branded model names
(DeepSeek, Kimi, GLM, etc.) now live in a new labelOverride field
instead of being embedded in route IDs.

- Backend auto-repairs legacy unsafe routes to the next free
  sonnet/opus/haiku slot instead of erroring
- Frontend swaps the free-form route input for a role dropdown plus
  menu display name field
- Add CLAUDE_DESKTOP_ROLE_ROUTE_IDS as the single source of truth
  for role-to-route mapping; presets and form both consume it
- Drop the dead displayName alias on ClaudeDesktopModelRoute and the
  ineffective /v1/models display_name injection (UI ignores it)
- Update i18n (en/ja/zh) and form focus test for the new fields

tests/components/ClaudeDesktopProviderForm.test.tsx

@@ -28,7 +28,7 @@ function renderForm(
 }
 
 describe("ClaudeDesktopProviderForm", () => {
-  it("编辑模型映射的 Desktop 模型 ID 时保持输入框焦点", () => {
+  it("编辑模型映射的菜单显示名时保持输入框焦点", () => {
     renderForm({
       name: "Proxy Provider",
       settingsConfig: {
@@ -47,15 +47,17 @@ describe("ClaudeDesktopProviderForm", () => {
       },
     });
 
-    const input = screen.getByPlaceholderText("gpt-5.5") as HTMLInputElement;
+    const input = screen.getByPlaceholderText(
+      "DeepSeek V4 Pro",
+    ) as HTMLInputElement;
     input.focus();
 
-    fireEvent.change(input, { target: { value: "12345" } });
+    fireEvent.change(input, { target: { value: "DeepSeek V4 Pro" } });
 
     const currentInput = screen.getByPlaceholderText(
-      "gpt-5.5",
+      "DeepSeek V4 Pro",
     ) as HTMLInputElement;
-    expect(currentInput).toHaveValue("12345");
+    expect(currentInput).toHaveValue("DeepSeek V4 Pro");
     expect(document.activeElement).toBe(currentInput);
   });