feat(pi): fetch and refresh upstream model lists, searchable model picker

- POST /pi/upstreams/{id}/models/refresh calls the provider's model list
  endpoint (OpenAI-shaped /models, Anthropic /v1/models, Google
  /v1beta/models, OpenRouter /api/v1/models; Radius via pi-ai refresh),
  normalizes {id, displayName, contextWindow, supportsVision,
  supportsTools, pricing} and stores it in pi_upstream.models (0044)
- GET .../models returns {source, fetchedAt, models[]}: remote merged
  with the static catalog (remote first); failures (401/network/
  unsupported) fall back to static with a one-line error
- POST /pi/models/probe for trying credentials before creating
- wizard and edit drawer: fetch button, searchable dropdown with
  vision/tool tags, manual id, source line; default upstream needs a model
- tests: mock /models, 401, network failure; smoke step; runbook

Co-Authored-By: Claude Opus 5.5 <[email protected]>

apps/web/scripts/smoke.mjs

@@ -215,6 +215,41 @@ async function main() {
     if (SHOTS) await page.screenshot({ path: join(OUT, `${name}.png`), fullPage: true }).catch(() => {});
     results.push({ path, ms: Date.now() - t0, problems: [...new Set(problems)] });
   }
+  // ── 交互:Agent 上游抽屉的模型选择(PI-2;只看来源行与可搜索下拉,不点「获取」,避免拿真实凭证出站)──
+  {
+    const label = "/console/settings#agent → 上游抽屉 · 模型选择";
+    const up = await page.request.get(`${BASE}/api/v1/pi/upstreams`);
+    const first = up.ok() ? (await up.json().catch(() => null))?.data?.items?.[0] : null;
+    if (!first) skipped.push(`${label}(没有上游)`);
+    else {
+      problems = [];
+      const t0 = Date.now();
+      try {
+        await page.goto("about:blank");
+        await page.goto(`${BASE}/console/settings#agent`, { waitUntil: "networkidle", timeout: 30_000 });
+        await page.getByText(first.name, { exact: true }).first().click();
+        const input = page.locator("#pu-model");
+        await input.waitFor({ timeout: 10_000 });
+        await page
+          .getByText(/^来源：/)
+          .first()
+          .waitFor({ timeout: 10_000 });
+        const models = (await page.request.get(`${BASE}/api/v1/pi/upstreams/${first.id}/models`).then((r) => r.json()))
+          ?.data?.models;
+        if (models?.length) {
+          await input.fill("");
+          await input.focus();
+          await page.locator('[role="listbox"] [role="option"]').first().waitFor({ timeout: 5_000 });
+        }
+        await page.keyboard.press("Escape");
+      } catch (err) {
+        problems.push(`交互失败:${String(err?.message ?? err).split("\n")[0]}`);
+      }
+      if (SHOTS) await page.screenshot({ path: join(OUT, "settings_agent_upstream_models.png") }).catch(() => {});
+      results.push({ path: label, ms: Date.now() - t0, problems: [...new Set(problems)] });
+    }
+  }
+
   // ── 旧链接重定向 ──
   for (const r of REDIRECT_ROUTES) {
     let from = r.from;