Plan-mode gate for artifact verify/upload consent is a hardcoded constant, not yet a real toggle

What

• A new module-level constant (Cdn, currently hardcoded to true) is now combined with plan-mode checks to broaden when certain artifact actions — like verify and upload_asset — require per-action confirmation rather than being covered by a session-wide approval. This matters because plan mode can admit third-party text into the conversation.
• The helper AA(e) that makes this decision resolves to Cdn && ue(e).mode === "plan", and is used together with another helper (Au()) throughout the new artifact consent code, including deciding whether comments or reads need a live confirmation prompt.
• A sibling helper, vU, resolves to (e.ask && e.basis === "unattended") || (EDe && ue(t).mode === "plan"), where EDe is a second constant currently set to true, gating a related plan-mode branch.

Why Both gating constants are hardcoded on rather than driven by a real setting, so today this behavior is effectively always active in plan mode: artifact verify/upload/comment/read actions get an explicit confirmation prompt rather than relying on a broader session approval, since plan mode can bring in untrusted third-party text.