feat(webui): refine output timeline and model controls (#4108)

* feat(webui): refine output timeline and composer queue

* feat(webui): add provider model picker

* fix(webui): polish model settings and heartbeat checks

* chore: keep heartbeat changes out of webui pr

* refactor(webui): isolate settings routes

* fix(providers): align minimax anthropic test

* fix(providers): keep minimax anthropic base sdk-compatible

* fix(providers): normalize anthropic base urls

webui/src/tests/thread-shell.test.tsx

@@ -270,7 +270,7 @@ describe("ThreadShell", () => {
     expect(await screen.findByTestId("composer-model-logo-openai_codex")).toBeInTheDocument();
   });
 
-  it("only shows image generation controls when the setting is enabled", async () => {
+  it("keeps image generation controls out of the composer", async () => {
     const client = makeClient();
     const disabledSettings = modelSettings("deepseek-v4-pro", "deepseek");
     const enabledSettings: SettingsPayload = {
@@ -313,7 +313,7 @@ describe("ThreadShell", () => {
       );
     });
 
-    expect(screen.getByRole("button", { name: "Toggle image generation mode" })).toBeInTheDocument();
+    expect(screen.queryByRole("button", { name: "Toggle image generation mode" })).not.toBeInTheDocument();
   });
 
   it("restores in-memory messages when switching away and back to a session", async () => {
@@ -1092,8 +1092,6 @@ describe("ThreadShell", () => {
     expect(screen.queryByText("Design an app icon")).not.toBeInTheDocument();
     expect(screen.queryByText("Write code")).not.toBeInTheDocument();
 
-    fireEvent.click(screen.getByRole("button", { name: "Toggle image generation mode" }));
-
     expect(screen.queryByText("Design an app icon")).not.toBeInTheDocument();
     expect(screen.queryByText("Write code")).not.toBeInTheDocument();
   });