fix(dashboard): fix budget section category colors and spending calcu…

[theperu]

🎯 Description

The dashboard's budget section was displaying incorrect category colors and missing spending from child categories. This PR fixes both issues by replacing the pre-computed monthlyBudgetsStatsProvider with direct use of budgetsProvider, monthlyTransactionsProvider, and allParentCategoriesProvider, moving the spending calculation to the widget layer for more accurate and transparent logic.

Closes: N/A

📱 Changes

• Fix budget indicators showing wrong colors — now uses category.color index instead of cycling by list position
• Fix spending calculation to include transactions from child categories via categoryParent
• Remove num.parse/toCurrency round-trip in spending calculation
• Replace manual ternaries with min/max for amount and perc
• Add division-by-zero guard when amountLimit is 0

🧪 Testing Instructions

Behaviour

1. Open the app and navigate to the Dashboard
2. Ensure at least one budget exists with a category that has sub-categories
3. Verify that the budget circular indicators display the correct category color (matching the color set in the category settings)
4. Add transactions under both the parent category and a child category
5. Verify that the spending amount and progress arc on the indicator correctly reflect the sum of all matching transactions

📸 Screenshots / Screen Recordings (if applicable)

If your PR involves UI changes, please add screenshots or screen recordings here.

Platform	Before	After
Android
iOS

🔍 Checklist for reviewers

• Code is formatted correctly
• Tests are passing
• New tests are added (if needed)
• Style matches the figma/designer requests
• Tested on:
  • iOS
  • Android