Subscription name now shown in role assignment summary

This patch fixes the azurerm_role_assignment summary line so that a mapped subscription display name is used instead of the raw subscription ID when the scope is at the subscription level.

🐛 Bug fixes

Fixed subscription-level role assignment summary showing raw ID instead of display name

Problem: When an azurerm_role_assignment resource had a subscription-level scope (e.g., scope = /subscriptions/12345678-...) and a subscription name mapping was configured, the <summary> line still showed the raw subscription ID instead of the friendly display name.

For example, with a mapping of { "id": "sub-123", "displayName": "Production" }, the summary incorrectly rendered as:

➕ azurerm_role_assignment my_assignment — 👤 Jane Doe → 🛡️ Contributor on subscription 🔑 sub-123

Fix: The BuildScopeSummary() method in RoleAssignmentViewModelFactory now consults the scope formatter for a subscription display name before falling back to the raw subscription ID — consistent with how the management group scope and the table scope attribute already behaved.

After the fix, the summary correctly renders as:

➕ azurerm_role_assignment my_assignment — 👤 Jane Doe → 🛡️ Contributor on subscription 🔑 Production

The table scope attribute continues to show the full 🔑 Production (sub-123) format (name + ID), unchanged.

Backward compatible: When no mapping exists, or when no scope formatter is provided, the summary falls back to the raw subscription ID as before.

Affected components

• AzureEntityMapper — Added GetSubscriptionName() method that returns just the display name (falling back to the raw ID when unmapped)
• EnrichedAzureScopeFormatter — Added GetSubscriptionName() delegating method
• RoleAssignmentViewModelFactory — Updated BuildScopeSummary() to use scopeFormatter.GetSubscriptionName() for subscription-level scopes

🧪 Test coverage

Added 5 new unit tests:

1. Build_WhenSubscriptionScopeAndMappingProvided_UsesMappedNameInSummary — verifies the summary shows the display name when a subscription mapping exists
2. Build_WhenSubscriptionScopeAndNoMapping_UsesIdInSummary — verifies fallback to raw ID when no mapping is configured
3. Build_WhenSubscriptionScopeAndNoScopeFormatter_UsesIdInSummary — verifies fallback to raw ID when no scope formatter is provided
4. AzureEntityMapper_GetSubscriptionName_ReturnsMappedDisplayName — verifies AzureEntityMapper.GetSubscriptionName returns just the display name (no ID suffix) when a mapping exists
5. AzureEntityMapper_GetSubscriptionName_FallsBackToRawId — verifies AzureEntityMapper.GetSubscriptionName returns the raw ID when no mapping is found

Added 2 subscription-level entries to the snapshot test data (role-assignments.json) and regenerated the snapshot:

• subscription_scope_mapped — scope /subscriptions/sub-123 with a display name of Production; summary shows 🔑 Production
• subscription_scope_unmapped — scope /subscriptions/sub-unmapped-id with no mapping; summary shows 🔑 sub-unmapped-id

All 1230 tests passing.