fix(proxy): keep the routing service running for Claude Desktop model mapping

Claude Desktop model-mapping providers send every request through the local
routing service, but the service lifecycle only counted the four routing apps:
when Claude Code left routing, stop_server_if_unused stopped the service Desktop
was still using, and nothing started it on launch.

- stop_server_if_unused now also treats a current Desktop model-mapping
  provider as a user of the service.
- ensure_desktop_mapping_service starts the service when that provider is in
  use; it runs on startup, after switching a Desktop provider and after
  applying a project that covers Claude Desktop.
- The frontend no longer warns that routing must be started when switching to
  a Desktop model-mapping provider, since the backend starts it; drop the now
  unused isProxyRunning hook argument and proxyReasonClaudeDesktop string.

tests/hooks/useProviderActions.test.tsx

@@ -233,7 +233,7 @@ describe("useProviderActions", () => {
       },
     });
 
-    const { result } = renderHook(() => useProviderActions("claude", false), {
+    const { result } = renderHook(() => useProviderActions("claude"), {
       wrapper,
     });
 
@@ -255,7 +255,7 @@ describe("useProviderActions", () => {
       },
     });
 
-    const { result } = renderHook(() => useProviderActions("codex", false), {
+    const { result } = renderHook(() => useProviderActions("codex"), {
       wrapper,
     });
 
@@ -275,7 +275,7 @@ describe("useProviderActions", () => {
       meta: { apiFormat: "anthropic" },
     });
 
-    const { result } = renderHook(() => useProviderActions("codex", false), {
+    const { result } = renderHook(() => useProviderActions("codex"), {
       wrapper,
     });
 
@@ -310,10 +310,9 @@ describe("useProviderActions", () => {
       }),
     ];
 
-    const { result } = renderHook(
-      () => useProviderActions("grokbuild", false),
-      { wrapper },
-    );
+    const { result } = renderHook(() => useProviderActions("grokbuild"), {
+      wrapper,
+    });
 
     for (const provider of providers) {
       await act(async () => {
@@ -336,10 +335,9 @@ describe("useProviderActions", () => {
       },
     });
 
-    const { result } = renderHook(
-      () => useProviderActions("codex", true, false),
-      { wrapper },
-    );
+    const { result } = renderHook(() => useProviderActions("codex", false), {
+      wrapper,
+    });
 
     await act(async () => {
       await result.current.switchProvider(provider);
@@ -362,8 +360,28 @@ describe("useProviderActions", () => {
       },
     });
 
+    const { result } = renderHook(() => useProviderActions("codex", true), {
+      wrapper,
+    });
+
+    await act(async () => {
+      await result.current.switchProvider(provider);
+    });
+
+    expect(toastWarningMock).not.toHaveBeenCalled();
+    expect(switchProviderMutateAsync).toHaveBeenCalledWith(provider.id);
+  });
+
+  it("does not warn for Claude Desktop model mapping, which starts routing itself", async () => {
+    switchProviderMutateAsync.mockResolvedValue(undefined);
+    const { wrapper } = createWrapper();
+    const provider = createProvider({
+      category: "custom",
+      meta: { claudeDesktopMode: "proxy" },
+    });
+
     const { result } = renderHook(
-      () => useProviderActions("codex", true, true),
+      () => useProviderActions("claude-desktop", false),
       { wrapper },
     );
 
@@ -375,36 +393,6 @@ describe("useProviderActions", () => {
     expect(switchProviderMutateAsync).toHaveBeenCalledWith(provider.id);
   });
 
-  it("uses proxy process readiness for Claude Desktop routing", async () => {
-    switchProviderMutateAsync.mockResolvedValue(undefined);
-    const { wrapper } = createWrapper();
-    const provider = createProvider({
-      category: "custom",
-      meta: { claudeDesktopMode: "proxy" },
-    });
-
-    const { result, rerender } = renderHook(
-      ({ isProxyRunning }) =>
-        useProviderActions("claude-desktop", isProxyRunning, false),
-      { initialProps: { isProxyRunning: true }, wrapper },
-    );
-
-    await act(async () => {
-      await result.current.switchProvider(provider);
-    });
-    expect(toastWarningMock).not.toHaveBeenCalled();
-
-    rerender({ isProxyRunning: false });
-    await act(async () => {
-      await result.current.switchProvider(provider);
-    });
-
-    expect(toastWarningMock).toHaveBeenCalledTimes(1);
-    expect(toastWarningMock).toHaveBeenCalledWith(
-      expect.stringContaining("Claude Desktop 本地路由模式"),
-    );
-  });
-
   it("allows the native Codex official provider during takeover", async () => {
     switchProviderMutateAsync.mockResolvedValueOnce(undefined);
     const { wrapper } = createWrapper();
@@ -413,10 +401,9 @@ describe("useProviderActions", () => {
       category: "official",
     });
 
-    const { result } = renderHook(
-      () => useProviderActions("codex", true, true),
-      { wrapper },
-    );
+    const { result } = renderHook(() => useProviderActions("codex", true), {
+      wrapper,
+    });
 
     await act(async () => {
       await result.current.switchProvider(provider);
@@ -433,10 +420,9 @@ describe("useProviderActions", () => {
       category: "official",
     });
 
-    const { result } = renderHook(
-      () => useProviderActions("claude", true, true),
-      { wrapper },
-    );
+    const { result } = renderHook(() => useProviderActions("claude", true), {
+      wrapper,
+    });
 
     await act(async () => {
       await result.current.switchProvider(provider);
@@ -462,10 +448,9 @@ describe("useProviderActions", () => {
         },
       },
     });
-    const { result } = renderHook(
-      () => useProviderActions("codex", true, true),
-      { wrapper },
-    );
+    const { result } = renderHook(() => useProviderActions("codex", true), {
+      wrapper,
+    });
 
     await act(async () => {
       await result.current.switchProvider(provider);