Implement auction results calculation logic

[VolodymyrBg]

Implements auction results calculation logic

This PR:

• Implements the auction results calculation logic in the marketplace-solver module
• Adds proper bid selection based on highest bid amount for each namespace
• Ensures each winning bid is only included once in the results
• Maintains the existing reserve bids functionality
• Reuses the permissionless implementation for the permissioned method

This PR does not:

• Change the database schema or API interfaces
• Modify the existing bid submission process
• Add additional validation for permissioned auctions (left for future work)

Key places to review:

• marketplace-solver/src/state.rs, calculate_auction_results_permissionless function
• marketplace-solver/src/state.rs, calculate_auction_results_permissioned function

Things tested

• Logic for selecting highest bids per namespace
• Handling of empty bid collections
• Proper inclusion of reserve bids in results

[x] Issue linked or PR description mentions why this change is necessary.
[x] PR description is clear enough for reviewers.
[x] Documentation for changes (additions) has been updated (added).
[x] If this is a draft it is marked as "draft".