feat(project-currency): implement project-specific currency support

- Added a currency column to the projects table to allow different projects to use different currencies.
- Updated existing projects to default to 'USD' if no currency is set.
- Enhanced project finance controller to handle currency retrieval and updates.
- Introduced API endpoints for updating project currency with validation.
- Updated frontend components to display and manage project currency effectively.

worklenz-backend/database/migrations/20250117000000-add-project-currency.sql

@@ -0,0 +1,20 @@
+-- Migration: Add currency column to projects table
+-- Date: 2025-01-17
+-- Description: Adds project-specific currency support to allow different projects to use different currencies
+
+-- Add currency column to projects table
+ALTER TABLE projects
+    ADD COLUMN IF NOT EXISTS currency VARCHAR(3) DEFAULT 'USD';
+
+-- Add comment for documentation
+COMMENT ON COLUMN projects.currency IS 'Project-specific currency code (e.g., USD, EUR, GBP, JPY, etc.)';
+
+-- Add constraint to ensure currency codes are uppercase and 3 characters
+ALTER TABLE projects
+    ADD CONSTRAINT projects_currency_format_check 
+    CHECK (currency ~ '^[A-Z]{3}$');
+
+-- Update existing projects to have a default currency if they don't have one
+UPDATE projects 
+SET currency = 'USD' 
+WHERE currency IS NULL;