Replace Unfilled Trades with New Signals#644

Currently, when the bot is configured to run a maximum number of simultaneous trades (e.g., 20 trades), it allocates slots for new trades as soon as signals are received. However, if some trades never reach their entry zone, they still occupy trade slots. This prevents the bot from taking potentially better opportunities when new signals arrive.

Proposed Enhancement:
If the bot has reached its maximum number of simultaneous trades but some trades are still pending entry, then:
When a new signal arrives, the bot should cancel one of the pending (untriggered) trades and place the new signal instead.
Priority could be based on:
Oldest pending signal (first-in, first-out).
Or configurable: cancel lowest-ranked signal (e.g., based on risk/reward or signal provider ranking).

Benefits:
Ensures trade slots aren’t wasted on signals that may never trigger.
Maximizes usage of the account’s capital by always favoring fresh, actionable signals.
Keeps the system more adaptive to current market conditions.