Add opt-in local durable review journal to agent actions #2469

Goal

Add an opt-in, local, durable journal for pending plans from POST /api/agents/actions, preserving the existing default behavior and Origin G.A.T.E. authority.

Acceptance criteria

• local-review-only blocks original action execution and requires trusted signed identity before the model call.
• Persist the exact pending plan through the Node bridge and Python SQLite/artifact journal, with idempotent actor scoping and verified byte receipts.
• Fail closed on missing configuration, invalid plans, unknown subprocess outcomes, unsupported serverless hosts, and tampered or missing evidence.
• Cover recovery, attempt budgets, denial, route integration, and default behavior with focused offline tests and CI.
• Document the local-only configuration, limitations, and review boundaries.

Scope

The journal is off by default. No live action adapter, hosted state store, credential creation, production activation, merge, or Origin G.A.T.E. PASS is included. A draft PR may produce a Vercel preview; production remains unchanged.