Sponsor gas and set the venue's required allowances on a wallet

The one-time onboarding step behind "enable trading": tops the wallet up with sponsored gas if it needs it, then sets every token allowance the venue's contracts require. Both legs are signed custodially with the user's delegated key. wait_for_confirmation defaults to true. The call then blocks until the work completes and the response reports what actually happened. Passing false returns immediately with confirmation_pending: true, success: true, gas_sponsored: false and allowances_set: 0 — success: true there means "accepted", not "done", and a background failure is only logged, never surfaced. Poll the RPC query exchange.getAllowances to find out whether it worked. The three identity fields are mandatory but are validated against the authenticated caller and the wallets it owns; they can confirm authority, never grant it. Self-custody callers on the external-signing lane should use POST /v2/onchain/intent with op: "approvals" instead and pay their own gas. Auth & scope. Requires trade:execute, the mutation gate (this endpoint spends gas-station funds, so a stolen JWT alone must not reach it), wallet ownership, and a current Turnkey policy version.