feat(platform): show deployment outbound IPs on adapter config forms

Cloud/NAT deployments couldn't complete WeCom-family / Official Account /
QQ Official setup because the trusted-IP (IP whitelist) value — the
server's egress IPs — was nowhere visible in LangBot.

- config.yaml: new system.outbound_ips list (env: SYSTEM__OUTBOUND_IPS,
  comma-separated), exposed via GET /api/v1/system/info
- dynamic form: generic __system.*-named display-only fields resolved
  from systemContext (same namespace as show_if), one read-only row per
  value with a copy button, excluded from form state and emitted values;
  hidden entirely when the deployment provides no IPs
- manifests: trusted-IP display field for wecom, wecomcs, wecombot,
  officialaccount, qqofficial

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/langbot/pkg/platform/sources/wecomcs.yaml

@@ -31,6 +31,18 @@ spec:
       type: webhook-url
       required: false
       default: ""
+    - name: __system.outbound_ips
+      label:
+        en_US: Trusted IPs
+        zh_Hans: 企业可信 IP
+        zh_Hant: 企業可信 IP
+      description:
+        en_US: Add these outbound IPs of the LangBot server to the "Trusted Enterprise IPs" of WeChat Customer Service in the WeCom admin console
+        zh_Hans: 请将这些 LangBot 服务器的出网 IP 添加到企业微信管理后台微信客服的「企业可信 IP」中
+        zh_Hant: 請將這些 LangBot 伺服器的出網 IP 加入企業微信管理後台微信客服的「企業可信 IP」中
+      type: array[string]
+      required: false
+      default: []
     - name: corpid
       label:
         en_US: Corpid