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/templates/config.yaml

@@ -21,6 +21,13 @@ system:
     recovery_key: ''
     allow_modify_login_info: true
     disabled_adapters: []
+    # Public outbound IP addresses of this LangBot deployment. Some platforms
+    # (e.g. WeCom, WeChat Official Account, QQ Official API) require the
+    # caller's IPs to be added to their trusted-IP / IP-whitelist settings.
+    # When set, the web UI shows these IPs on the bot config form of such
+    # adapters. Also settable via the SYSTEM__OUTBOUND_IPS env var
+    # (comma-separated). Empty list = hidden in the web UI.
+    outbound_ips: []
     limitation:
         max_bots: -1
         max_pipelines: -1