feat(explorer): service metric cards on the service page

### Description

Above the rails/dataset content, show four cards for the payer/operator pair: recurring spend per month, one-time ops spend, account-level runway, and locked deposit. Locked deposit copy states the deposit returns on terminate.

Spend and locked come from the pair's rails, pricing from `getServicePrice()`, runway from account funds and lockup rate. These were already real (not `PocChip`) in the POC branch; this is porting them onto #409's page.

### Additional context

Parent: #460. Depends on #409. Not a Warm Storage-only feature, but the one-time ops split only means something for FWSS today.

Merges alone: cards read from rails and contract calls that exist today; no new subgraph dependency.

Start with the service page from #409 and inspect how its rails and contract calls expose payer/operator data. Check the existing getServicePrice(), account funds, and lockup rate sources. Done means four cards show recurring monthly spend, one-time ops spend, account-level runway, and locked deposit, with the stated termination copy.

Written by the indexing model from the issue text.