refactor(web): replace query option tunneling with queryOptions factories

Extract sandboxFilesTreeOptions and buildTreeFromFlatList from
useSandboxFilesTree so callers that need custom TanStack Query behavior
(e.g. refetchInterval) can compose at the call site instead of tunneling
options through the hook. Remove the thin useGetSandboxProviderList
wrapper in favor of inline oRPC queryOptions in the component.

Also remove redundant .input(type<unknown>()) from three no-input GET
contracts—oc already defaults TInputSchema to Schema<unknown, unknown>.

web/contract/console/billing.ts

@@ -6,7 +6,6 @@ export const invoicesContract = base
     path: '/billing/invoices',
     method: 'GET',
   })
-  .input(type<unknown>())
   .output(type<{ url: string }>())
 
 export const bindPartnerStackContract = base

web/contract/console/sandbox-provider.ts

@@ -7,7 +7,6 @@ export const getSandboxProviderListContract = base
     path: '/workspaces/current/sandbox-providers',
     method: 'GET',
   })
-  .input(type<unknown>())
   .output(type<SandboxProvider[]>())
 
 export const saveSandboxProviderConfigContract = base

web/contract/console/system.ts

@@ -7,5 +7,4 @@ export const systemFeaturesContract = base
     path: '/system-features',
     method: 'GET',
   })
-  .input(type<unknown>())
   .output(type<SystemFeatures>())