azure-prepare: add Table Storage recipe routing and explicit Table RBAC guidance for Functions

[Copilot]

azure-prepare did not provide a Table Storage recipe path, and Functions guidance implied Blob role coverage was sufficient for tables. This caused generated deployments to miss Storage Table Data Contributor, leading to runtime authorization failures.

• Template selection + composition updates

  • Added Table Storage detection signals to the Functions selection guide:
    • TableServiceClient, TableClient, Azure.Data.Tables, @azure/data-tables
  • Added composition rule to use HTTP base + table-storage recipe when Table SDK usage is present.

• New Table Storage recipe reference

  • Added references/services/functions/templates/recipes/table-storage/README.md
  • Documents:
    • when to apply the recipe
    • required Table RBAC assignment
    • troubleshooting for 500/unauthorized table access due to missing or unpropagated RBAC.

• RBAC guidance corrections in Functions references

  • Updated Functions Bicep guidance to include explicit Storage Table Data Contributor assignment for Table workloads.
  • Updated Terraform guidance to state Blob role is for runtime/deployment blob access, and Table role must be added for Table SDK access.

• Recipes index

  • Added table-storage to the recipes catalog.

resource tableRoleAssignment 'Microsoft.Authorization/roleAssignments@2022-04-01' = {
  name: guid(storageAccount.id, functionApp.id, 'Storage Table Data Contributor')
  scope: storageAccount
  properties: {
    roleDefinitionId: subscriptionResourceId(
      'Microsoft.Authorization/roleDefinitions',
      '0a9a7e1f-b9d0-4cc4-a60d-0319b160aaa3'
    )
    principalId: functionApp.identity.principalId
    principalType: 'ServicePrincipal'
  }
}