UI: Delete saved dashboard view

[TerrifiedBug]

Problem

Saved dashboard views support Create, Update, and List in the UI (trpc.dashboard.createView and updateView in src/components/dashboard/view-builder-dialog.tsx + custom-view.tsx; listViews query), but Delete is missing.

dashboard.deleteView (src/server/routers/dashboard.ts:772) — withTeamAccess("VIEWER"), audited (dashboard.delete_view) — has no client caller, so users can accumulate saved views with no way to remove them.

Proposed solution

Add a Delete affordance to the saved-views UI (src/components/dashboard/custom-view.tsx):

• A per-view delete control (menu item or trash icon) calling dashboard.deleteView with { environmentId, id }.
• Confirm before delete; on success invalidate the ["dashboard","listViews"] query (same pattern the create/update mutations already use).

Alternatives considered

• Leave deletion to a future bulk-management screen — overkill; the gap is one missing verb in an otherwise-complete CRUD surface.

Additional context

Completes CRUD for saved views. Input: { environmentId, id }. Mirror the onSuccess cache-invalidation already in view-builder-dialog.tsx.

Part of #431

[TerrifiedBug]

⚠️ Partially addressed (closes on merge for the delete wiring).

dashboard.deleteView is now wired — per-view delete with a confirm dialog in the view-builder dialog (src/components/dashboard/view-builder-dialog.tsx), mirroring the existing create/update onSuccess + listViews invalidation.

Caveat / follow-up worth tracking: the saved-views components (ViewBuilderDialog / CustomView) are currently orphaned — not imported or mounted by any page. The dashboard (src/app/(dashboard)/page.tsx) renders its own metrics layout and never mounts them, and there is no dashboard.listViews consumer in the tree. So create / update / delete views are all unreachable by users today. Making the saved-views feature reachable (mounting a view list + selection on the dashboard) is a separate, larger gap beyond this delete-wiring slice — flagging it under epic #431.