add conversation expire config & user query text to dingtalk card (#2147)

* add conversation expire config

* add user query text to card

* fix(pipeline): move session limit to AI config

* test(pipeline): cover AI session limit config

* refactor(pipeline): merge session expire-time into AI runner stage

Move the session validity duration field out of the standalone
session-limit stage into the runner stage so it actually renders in the
AI tab (the tab only shows the runner stage and the stage matching the
selected runner — any other stage is filtered out). Read path, default
config, metadata description, and tests updated accordingly.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix(pipeline): expire conversations from last update time

* fix(n8n): sync generated conversation id into payload

---------

Co-authored-by: RockChinQ <rockchinq@gmail.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/langbot/templates/metadata/pipeline/safety.yaml

@@ -72,4 +72,4 @@ stages:
           - name: wait
             label:
               en_US: Wait
-              zh_Hans: 等待
+              zh_Hans: 等待