BOLT-1267 Phase 1: Program Events — simulated event curve preview (sane-assumption)

New EventCurvePreview.tsx in apps/dashboard/packs/programs/routes/(programs)/events/_components/. Stepped power-vs-time chart from action sequence alone — no telemetry. Signed kW Y axis, action timeline X axis, shaded reserve floor band, color-coded mode segments. Three design questions pending Richie before kicking off (Y units, reserve render style, charge convention). Phase 2 (device-aware) + Phase 3 (historical overlay) separately scoped. Linear: BOLT-1267 — https://linear.app/texture/issue/BOLT-1267