[WIP] Support Multiple Currencies per Provider and Provision Node

[chibie]

User Story
As a provider, I want to support multiple currencies in my provision node to expand my service offering and handle payments in different fiat currencies.

Acceptance Criteria

1. GIVEN a user signs up as a provider,
   WHEN they specify currencies,
   THEN they should be able to select one or more supported currencies

2. GIVEN a provider profile exists,
   WHEN querying provider rates,
   THEN the rate should be specific to the requested currency

3. GIVEN a provision node is configured,
   WHEN reading currency configuration,
   THEN it should support multiple currencies from environment variables

4. GIVEN a provision node starts up,
   WHEN registering with PSPs,
   THEN it should register for all configured currencies

5. GIVEN a provider supports multiple currencies,
   WHEN the priority queue selects providers,
   THEN it should match providers based on supported currencies

Tech Details

• Schema Changes:

  • Update ProviderProfile schema to support many-to-many relationship with FiatCurrency
  • Add association table for provider-currency relationships
  • Update provider creation endpoint

• API Changes:

  • Modify signup payload to accept array of currencies
  • Update provider rate queries to filter by currency
  • Add currency parameter to GetProviderRate function
  • Update rate calculation logic for multiple currencies

• Provision Node Updates:

  • Change Currency env var to SupportedCurrencies (string array)
  • Update config parsing to handle multiple currencies
  • Modify PSP registration to handle all supported currencies
  • Update rate calculation for each currency

Example Changes:

// Provider profile creation
provider, err := tx.ProviderProfile.
   Create().
   AddCurrencies(currencies...).
   SetVisibilityMode(providerprofile.VisibilityModePrivate).
   SetUser(user).
   SetProvisionMode(providerprofile.ProvisionModeAuto).
   Save(ctx)

// GetProviderRate with currency
func (s *PriorityQueueService) GetProviderRate(
   ctx context.Context, 
   provider *ent.ProviderProfile, 
   token string,
   currency string,
) (decimal.Decimal, error) {
   // Add currency to query filters
}

[Supa-mega]

May I handle this issue?