Providers factory (#250)

* Implement providers factory

* Multiple providers sync support

- Proper Multi-Provider Syncing: When you click sync on an account with multiple providers (e.g., both Plaid and SimpleFin), all provider items are synced
- Better API: The existing account.providers method already returns all providers, and account.provider returns the first one for backward compatibility
- Correct Holdings Deletion Logic: Holdings can only be deleted if ALL providers allow it, preventing accidental deletions that would be recreated on next sync
TODO: validate this is the way we want to go? We would need to check holdings belong to which account, and then check provider allows deletion. More complex
- Database Constraints: The existing validations ensure an account can have at most one provider of each type (one PlaidAccount, one SimplefinAccount, etc.)

* Add generic provider_import_adapter

* Finish unified import strategy

* Update app/models/plaid_account.rb

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Signed-off-by: soky srm <sokysrm@gmail.com>

* Update app/models/provider/factory.rb

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Signed-off-by: soky srm <sokysrm@gmail.com>

* Fix account linked by plaid_id instead of external_id

* Parse numerics to BigDecimal

Parse numerics to BigDecimal before computing amount; guard nils.

Avoid String * String and float drift; also normalize date.

* Fix incorrect usage of assert_raises.

* Fix linter

* Fix processor test.

* Update current_balance_manager.rb

* Test fixes

* Fix plaid linked account test

* Add support for holding per account_provider

* Fix proper account access

Also fix account deletion for simpefin too

* FIX match tests for consistency

* Some more factory updates

* Fix account schema for multipe providers

  Can do:
  - Account #1 → PlaidAccount + SimplefinAccount (multiple different providers)
  - Account #2 → PlaidAccount only
  - Account #3 → SimplefinAccount only

  Cannot do:
  - Account #1 → PlaidAccount + PlaidAccount (duplicate provider type)
  - PlaidAccount #123 → Account #1 + Account #2 (provider linked to multiple accounts)

* Fix account setup

- An account CAN have multiple providers (the schema shows account_providers with unique index on [account_id, provider_type])
  - Each provider should maintain its own separate entries
  - We should NOT update one provider's entry when another provider syncs

* Fix linter and guard migration

* FIX linter issues.

* Fixes

- Remove duplicated index
- Pass account_provider_id
- Guard holdings call to avoid NoMethodError

* Update schema and provider import fix

* Plaid doesn't allow holdings deletion

* Use ClimateControl for proper env setup

* No need for this in .git

---------

Signed-off-by: soky srm <sokysrm@gmail.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Co-authored-by: Juan José Mata <juanjo.mata@gmail.com>

app/models/plaid_account/processor.rb

@@ -30,9 +30,20 @@ class PlaidAccount::Processor
 
     def process_account!
       PlaidAccount.transaction do
-        account = family.accounts.find_or_initialize_by(
-          plaid_account_id: plaid_account.id
-        )
+        # Find existing account through account_provider or legacy plaid_account_id
+        account_provider = AccountProvider.find_by(provider: plaid_account)
+        account = if account_provider
+          account_provider.account
+        else
+          # Legacy fallback: find by plaid_account_id if it still exists
+          family.accounts.find_by(plaid_account_id: plaid_account.id)
+        end
+
+        # Initialize new account if not found
+        if account.nil?
+          account = family.accounts.new
+          account.accountable = map_accountable(plaid_account.plaid_type)
+        end
 
         # Create or assign the accountable if needed
         if account.accountable.nil?
@@ -65,6 +76,15 @@ class PlaidAccount::Processor
 
         account.save!
 
+        # Create account provider link if it doesn't exist
+        unless account_provider
+          AccountProvider.find_or_create_by!(
+            account: account,
+            provider: plaid_account,
+            provider_type: "PlaidAccount"
+          )
+        end
+
         # Create or update the current balance anchor valuation for event-sourced ledger
         # Note: This is a partial implementation. In the future, we'll introduce HoldingValuation
         # to properly track the holdings vs. cash breakdown, but for now we're only tracking