Verify the pair universe actually used in a backtest

Goal

Validate a research pair universe and produce a static snapshot usable by Freqtrade backtesting.

Steps

1. Define the research pairs and static filters in the config; dynamic VolumePairList and PercentChangePairList, among others, cannot be used for Freqtrade backtesting. [pairlists]
2. Run freqtrade test-pairlist --config user_data/config.json --quote USDT --print-json against the current config and inspect the filtered result and exchange availability. [test-pairlist]
3. Copy the approved pairs into a StaticPairList config snapshot and record its generation time, exchange, and config version; do not pass a dynamic pairlist directly to backtesting. [pairlists]
4. Run freqtrade backtesting --config user_data/config.json --strategy MyStrategy with that static snapshot and archive the snapshot alongside the backtest results. [pairlists]

How to verify

The `test-pairlist` output is reviewed and approved, the backtest uses the same `StaticPairList` snapshot, and no dynamic plugin is in its config.

Troubleshooting

If `test-pairlist` returns no pairs or unexpected pairs, inspect the allowlist, filter order, and market type; use a static list for backtesting because dynamic pairlists are unsupported there.