Dynamic strategy parameters in Backtesting UI

[khoren93]

First of all, thank you for all the hard work on FreqUI! It's an amazing tool that makes managing Freqtrade bots so much easier.

Is your feature request related to a problem? Please describe.
I'm frustrated when I need to test different strategy parameters (like DecimalParameter, IntParameter, etc.) in the UI. Currently, the Backtest window only allows changing global settings (timerange, timeframe, stake). To tweak a specific strategy value (e.g., changing an indicator threshold), a user has to manually edit the Python strategy file or the JSON configuration. This is a significant barrier for traders who are not developers or don't want to touch the code for every test run.

Describe the solution you'd like
I'd like the Backtest window to dynamically fetch the available parameters for the selected strategy (using the existing /strategy/<name> endpoint) and display them as editable fields.

• The UI should automatically generate input fields based on the parameter type (e.g., sliders for ranges, numeric inputs for decimals).
• It should ideally focus on parameters where optimize=True is set in the strategy.
• When clicking "Start Backtest", these overridden values should be included in the BacktestPayload sent to the API, allowing the backend to apply them for that specific run without modifying the source files.

Describe alternatives you've considered

• Manually editing the .py strategy file (slow and prone to errors for non-coders).
• Maintaining multiple JSON configuration files for different parameter sets (hard to manage).
• Using the CLI for backtesting with --strategy-list (defeats the purpose of using a GUI).

Additional context
The codebase already has definitions for these parameters in strategy.ts (AllStrategyParameter) and a way to view them in StrategyParameters.vue. Extending this logic to BacktestRun.vue would make the UI a much more powerful tool for strategy fine-tuning.

[xmatthias]

@hiSandog i'm not sure how this comment relates to this issue, really.
the different parameter types are WAY less problematic than you think (not sure why DecimalParameter would deserve an edge-case, really).

Adding the parameter modification per se is not problematic. that's just a couple changes across freqtrade/frequi, really.

The bigger problem here is the subsequent workflow - as in - "i used intparam=15 for my backtest, how do i get that to the running strategy".
i'd not want the manual params to overwrite the strategy params by default - but we still need an intuitive way to say "ok, the 3rd-last backtest was the best, now let's run this in live" without having to somehow manually extract all parameters.