Refactor Plaid transaction type mapping and improve label handling

- Updated `PLAID_TYPE_TO_LABEL` in `TransactionsProcessor` to consolidate labels ("Cancel" and "Cash" now mapped to "Other").
- Adjusted `label_from_plaid_type` to return "Other" as the default fallback.
- Enhanced tests to include additional valid activity labels and ensure label consistency.
- Minor fixes to locale keys for transaction views.

app/models/plaid_account/investments/transactions_processor.rb

@@ -2,11 +2,12 @@ class PlaidAccount::Investments::TransactionsProcessor
   SecurityNotFoundError = Class.new(StandardError)
 
   # Map Plaid investment transaction types to activity labels
+  # All values must be valid Transaction::ACTIVITY_LABELS
   PLAID_TYPE_TO_LABEL = {
     "buy" => "Buy",
     "sell" => "Sell",
-    "cancel" => "Cancelled",
-    "cash" => "Cash",
+    "cancel" => "Other",
+    "cash" => "Other",
     "fee" => "Fee",
     "transfer" => "Transfer",
     "dividend" => "Dividend",
@@ -92,7 +93,7 @@ class PlaidAccount::Investments::TransactionsProcessor
 
     def label_from_plaid_type(transaction)
       plaid_type = transaction["type"]&.downcase
-      PLAID_TYPE_TO_LABEL[plaid_type] || plaid_type&.titleize
+      PLAID_TYPE_TO_LABEL[plaid_type] || "Other"
     end
 
     def transactions

app/models/transaction.rb

@@ -17,7 +17,7 @@ class Transaction < ApplicationRecord
     cc_payment: "cc_payment", # A CC payment, excluded from budget analytics (CC payments offset the sum of expense transactions)
     loan_payment: "loan_payment", # A payment to a Loan account, treated as an expense in budgets
     one_time: "one_time", # A one-time expense/income, excluded from budget analytics
-    investment_contribution: "investment_contribution" # Transfer to investment/crypto account, included in budget as investment expense
+    investment_contribution: "investment_contribution" # Transfer to investment/crypto account, excluded from budget analytics
   }
 
   # All valid investment activity labels (for UI dropdown)