Add comprehensive test coverage for Contracts View Page

[Copilot]

Improve Code Coverage on Contracts View Page

Based on analysis of EstateIndexPageTests as a reference, added comprehensive tests for:

• Button finding and clicking: Test "Back to List" button functionality
• Navigation verification: Verify BackToList navigates to /contracts
• Loading state verification: Test loading spinner display
• Products display: Test products section when present and empty
• Transaction fees display: Test transaction fees rendering
• Error scenarios: Test for contract not found state
• Contract not found: Test "Contract not found" state and back button
• Fix build errors: Added missing using statements and corrected model types

Added 9 new tests following EstateIndexPageTests patterns:

• ContractsView_HasBackButton
• ContractsView_BackButton_NavigatesToContractsList
• ContractsView_DisplaysProducts_WhenPresent
• ContractsView_DisplaysNoProducts_WhenEmpty
• ContractsView_DisplaysTransactionFees_WhenPresent
• ContractsView_LoadContract_QueryFails_ShowsNotFoundMessage
• ContractsView_LoadContract_ReturnsNull_ShowsNotFoundMessage
• ContractsView_ContractNotFound_HasBackButton
• ContractsView_ContractNotFound_BackButton_NavigatesToContractsList

Total tests: 12 (was 3, added 9)

Build fixes:

• Added using AngleSharp.Dom; for IElement type
• Removed using EstateManagementUI.BlazorServer.Models; to avoid ambiguous references
• Used BusinessLogic.Models types consistently (ProductType as string, CalculationType/FeeType as int)

Original prompt

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This section details on the original issue you should resolve

<issue_title>Improve Code Coverage on Contracts View Page</issue_title>
<issue_description>Use the estate index page tests as a guide on how to find buttons and also verify navigation</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Improve Code Coverage on Contracts View Page #718

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[StuartFerguson]

@copilot code failed to build

[Copilot]

@copilot code failed to build

Fixed in commit 8165127. The build errors were caused by:

1. Missing using AngleSharp.Dom; for the IElement type
2. Ambiguous reference to ContractModel due to importing both EstateManagementUI.BlazorServer.Models and EstateManagementUI.BusinessLogic.Models - removed the BlazorServer.Models import
3. Incorrect types for enum properties - BusinessLogic.Models uses string for ProductType and int for CalculationType/FeeType

The tests now use BusinessLogic.Models consistently, matching the pattern in EstateIndexPageTests.