feat(agent): support Responses steering and project-aware tools

Use the dedicated TJWATER_AGENT_URL and Responses stream protocol. Keep running
turns active while users steer or queue follow-ups and edit pending delivery.
Refresh the model catalog before generation and preserve approval mode selection.

Integrate scoped investigation messaging/presentation, geographic place selection,
current Agent composer styles and supporting workbench contracts.

Validation: 77 focused Vitest checks, 21 browser cases, lint, typecheck and
production build. Preserve direct Server/Agent routing and project authentication.

tests/browser/agent-select-menu.e2e.ts

@@ -7,7 +7,7 @@ test.beforeEach(async ({ page }) => {
   await page.emulateMedia({ reducedMotion: "reduce" });
   await mockWorkbenchContext(page);
   await mockAgentApi(page);
-  await page.route("**/api/v1/agent/chat/models", (route) => route.fulfill({
+  await page.route("**/api/v1/models", (route) => route.fulfill({
     headers: { "Access-Control-Allow-Origin": "*" },
     json: {
       default_model: "test/fast",
@@ -59,8 +59,8 @@ for (const width of [1440, 375]) {
     const trigger = page.locator('button[aria-label="权限批准模式"]');
     await trigger.click();
     await waitForMenuAnimations(page.getByRole("menu"));
-    const request = page.getByRole("menuitem", { name: /工具权限逐次确认/ });
-    const always = page.getByRole("menuitem", { name: /自动允许本轮权限请求/ });
+    const request = page.getByRole("menuitem", { name: /需要审批的请求逐次确认/ });
+    const always = page.getByRole("menuitem", { name: /自动批准本轮工具权限请求/ });
     for (const item of [request, always]) {
       await item.hover();
       await expectThemeColor(item, "background-color", "--action-selection-soft-hover");
@@ -85,6 +85,81 @@ for (const width of [1440, 375]) {
   });
 }
 
+test("sends the selected approval mode and can return to manual approval", async ({ page }) => {
+  await page.goto("/", { waitUntil: "domcontentloaded" });
+  await page.getByRole("button", { name: /展开 Agent 助手面板/ }).click();
+  const trigger = page.getByRole("button", { name: "权限批准模式" });
+
+  for (const [label, mode] of [
+    ["自动批准本轮工具权限请求", "always"],
+    ["需要审批的请求逐次确认", "request"],
+  ] as const) {
+    await expect(trigger).toBeEnabled();
+    await trigger.click();
+    await page.getByRole("menuitem", { name: new RegExp(label) }).click();
+    await page.getByRole("textbox", { name: "询问供水问题，或描述需要处理的任务" }).fill(`验证权限模式 ${mode}`);
+    const sent = page.waitForRequest((request) => request.method() === "POST" && request.url().endsWith("/api/v1/responses"));
+    await page.getByRole("button", { name: "发送 Agent 指令" }).click();
+    expect((await sent).postDataJSON().tjwater.approval_mode).toBe(mode);
+  }
+  await expect(trigger).toBeEnabled();
+});
+
+test("replaces a removed model before sending and shows the model actually submitted", async ({ page }) => {
+  await page.goto("/", { waitUntil: "domcontentloaded" });
+  await page.getByRole("button", { name: /展开 Agent 助手面板/ }).click();
+  const trigger = page.getByRole("button", { name: "选择 Agent 模型" });
+  await expect(trigger).toHaveAccessibleDescription("当前模型：快速");
+  await trigger.click();
+  await page.getByRole("menuitem", { name: /深入分析和复杂任务处理/ }).click();
+  await expect(trigger).toHaveAccessibleDescription("当前模型：专家");
+
+  // Simulate an Agent restart with a new catalog while this page stays open.
+  await page.route("**/api/v1/models", (route) => route.fulfill({
+    headers: { "Access-Control-Allow-Origin": "*" },
+    json: {
+      default_model: "waternetwork/gpt-6-luna",
+      models: [{ id: "waternetwork/gpt-6-luna", label: "快速", description: "当前可用模型", icon: "bolt" }]
+    }
+  }));
+  await page.getByRole("textbox", { name: "询问供水问题，或描述需要处理的任务" }).fill("检查更新后的快速模型");
+  const sent = page.waitForRequest((request) => request.method() === "POST" && request.url().endsWith("/api/v1/responses"));
+  await page.getByRole("button", { name: "发送 Agent 指令" }).click();
+  expect((await sent).postDataJSON().model).toBe("waternetwork/gpt-6-luna");
+  await expect(trigger).toHaveAccessibleDescription("当前模型：快速");
+});
+
+test("keeps an explicitly selected model when it remains available", async ({ page }) => {
+  await page.goto("/", { waitUntil: "domcontentloaded" });
+  await page.getByRole("button", { name: /展开 Agent 助手面板/ }).click();
+  const trigger = page.getByRole("button", { name: "选择 Agent 模型" });
+  await expect(trigger).toHaveAccessibleDescription("当前模型：快速");
+  await trigger.click();
+  await page.getByRole("menuitem", { name: /深入分析和复杂任务处理/ }).click();
+  await page.getByRole("textbox", { name: "询问供水问题，或描述需要处理的任务" }).fill("保留专家模型选择");
+  const sent = page.waitForRequest((request) => request.method() === "POST" && request.url().endsWith("/api/v1/responses"));
+  await page.getByRole("button", { name: "发送 Agent 指令" }).click();
+  expect((await sent).postDataJSON().model).toBe("test/expert");
+  await expect(trigger).toHaveAccessibleDescription("当前模型：专家");
+});
+
+test("does not send a generation request when the refreshed catalog is empty", async ({ page }) => {
+  await page.goto("/", { waitUntil: "domcontentloaded" });
+  await page.getByRole("button", { name: /展开 Agent 助手面板/ }).click();
+  await expect(page.getByRole("button", { name: "选择 Agent 模型" })).toHaveAccessibleDescription("当前模型：快速");
+  await page.route("**/api/v1/models", (route) => route.fulfill({
+    headers: { "Access-Control-Allow-Origin": "*" }, json: { default_model: "test/fast", models: [] }
+  }));
+  const requests: string[] = [];
+  page.on("request", (request) => {
+    if (request.method() === "POST" && request.url().endsWith("/api/v1/responses")) requests.push(request.url());
+  });
+  await page.getByRole("textbox", { name: "询问供水问题，或描述需要处理的任务" }).fill("检查空模型目录");
+  await page.getByRole("button", { name: "发送 Agent 指令" }).click();
+  await expect(page.getByText("Agent 后端当前没有可用模型，请检查模型配置。").first()).toBeVisible();
+  expect(requests).toEqual([]);
+});
+
 async function waitForMenuAnimations(menu: Locator) {
   await expect(menu).toBeVisible();
   await menu.evaluate((element) => Promise.all(