Fix A token DCA gas issues

[mrq1911]

Currently scheduling dca can fail because gas limit was hit during reserving of assets, this can be overcame by wrapping it with extra gas. However, is very likely the following execution itself will fail as well then on gas limit.

This can be fixed by transfering reserved balance straight to the DCA and bypassing account that would require that extra gas, but in the case of unbudgeted DCA the extra gas just have to be supplied to enable transfer.

• bypass user account when transferring from reserve

If previous DCA execution fails on out of gas (requires #1206), increase gas limit by (max extra gas / max retries) clamped to max extra gas.

• Better EVM error handling #1206
• retry on outofgas
• store max & current extra gas of schedule
• add optional param for max extra gas which will be charged on every execution (and possibly schedule as well, default will be 1_000_000)

[dmoka]

DCA Extra Gas Handling Specification

Overview

Handle AToken action failures due to gas limits by incrementally increasing extra gas on each retry until successful execution is achieved.

Constants

• MAX_EXTRA_GAS: Maximum extra gas that can be added (constant value - 1_000_000 gas units)

Storage

ScheduleExtraGas: StorageMap<ScheduleId, u64>

• Stores the current extra gas value for each schedule
• Initialized to 0 when schedule is created
• Persists across executions once a working value is found

Retry Logic on OutOfGas

When a DCA execution fails with OutOfGas error:

1. Calculate increment: gas_increment = MAX_EXTRA_GAS / max_retries_of_schedule
2. Increase extra gas: ScheduleExtraGas[schedule_id] += gas_increment
3. Retry schedule using existing retry mechanism

Pre-Execution

Before executing a DCA trade:

1. Read extra_gas = ScheduleExtraGas[schedule_id]
2. Write to pallet_dispatcher::ExtraGas::set(extra_gas)
3. Execute the trade

On Successful Execution

• Keep the current ScheduleExtraGas[schedule_id] value unchanged
• Use this same value for all future executions of this schedule

Fee Calculation

When calculating transaction fees before execution:

1. Get base weight: base_weight = get_trade_weight(order)
2. Convert extra gas to weight: extra_weight = GasWeightMapping::gas_to_weight(extra_gas)
3. Total weight for fee: total_weight = base_weight + extra_weight
4. Charge fee based on total_weight

Cleanup

Remove ScheduleExtraGas[schedule_id] when schedule is terminated or completed (in remove_schedule_from_storages).

Implementation Notes

• OutOfGas errors should be added to RetryOnError configuration
• The extra gas value is never decreased for a schedule once increased
• Each schedule maintains its own extra gas value independently
• The gas increment is linear: each retry adds the same amount