[RiskeyL]

Brings the two fixes that reached main only through #1127 back to release/1.18.0, so the release branch matches the published 1.18.0 docs:

• Workflow 101 lesson 4: the Knowledge Retrieval field is Knowledge Base in en (renamed in the 1.18.0 tag); the ja page also uses the node's 知識検索 name and the field's ナレッジベース label.
• Agent tracing env rows: Agents inside a workflow tool the app calls aren't traced, each app also needs Capture Agent internals on, and the reconcile task's retention deletes only the trace data Dify stores.

Refs DC-408

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