refactor(agent): runAgent uses Agent upstreams only; deprecate legacy settings.pi fields

pi.provider / baseUrl / model / thinkingLevel / apiKeySecretRef are now
DEPRECATED_SETTINGS_FIELDS: kept in the schema for stored JSON, dropped
from PATCH /settings and from the settings sections, never read by the
server. runAgent fails with a clear message when no upstream is set.
The agent demo gate checks the default upstream provider; e2e seeds a
fake upstream as default. OpenAPI summaries say Agent upstream.

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

packages/contracts/src/api.ts

@@ -1246,14 +1246,14 @@ export const Api = {
       method: "get",
       path: "/pi/upstreams",
       scope: "admin",
-      summary: "Pi 上游列表(不含密钥)",
+      summary: "Agent 上游列表(不含密钥)",
       response: pi.PiUpstreamList,
     }),
     get: ep({
       method: "get",
       path: "/pi/upstreams/{id}",
       scope: "admin",
-      summary: "Pi 上游详情",
+      summary: "Agent 上游详情",
       params: IdParam,
       response: pi.PiUpstream,
     }),
@@ -1262,7 +1262,7 @@ export const Api = {
       path: "/pi/upstreams",
       scope: "admin",
       auth: "session",
-      summary: "新建 Pi 上游(apiKey 只写,存 secret 表)",
+      summary: "新建 Agent 上游(apiKey 只写,存 secret 表)",
       body: pi.PiUpstreamCreate,
       response: pi.PiUpstream,
     }),
@@ -1271,7 +1271,7 @@ export const Api = {
       path: "/pi/upstreams/{id}",
       scope: "admin",
       auth: "session",
-      summary: "修改 Pi 上游(provider 不可改;makeDefault 设默认上游)",
+      summary: "修改 Agent 上游(provider 不可改;makeDefault 设默认上游)",
       params: IdParam,
       body: pi.PiUpstreamUpdate,
       response: pi.PiUpstream,
@@ -1281,7 +1281,7 @@ export const Api = {
       path: "/pi/upstreams/{id}",
       scope: "admin",
       auth: "session",
-      summary: "删除 Pi 上游(连同凭据;是默认上游时清空默认)",
+      summary: "删除 Agent 上游(连同凭据;是默认上游时清空默认)",
       params: IdParam,
       response: OkResult,
     }),