M5: Blazor dashboard (MudBlazor + ApexCharts)

- MudBlazor theme (dark default) + responsive drawer/appbar layout + nav.
- DashboardService read model: KPIs with period-over-period deltas, category breakdown,
  "what cost more/less" difference view, monthly trends.
- Pages: Overview (KPI cards + DeltaChip + donut + difference table), Trends (range-select
  bar chart), Meters (list + source status), Import (load reference dataset + CSV dry-run
  preview), Admin (energy types, tariffs). Charts isolated into components to avoid the
  ApexCharts/MudBlazor Color/Format name clashes.
- ReferenceDataImporter: one-click load of all four sheets as a starter dataset (meters,
  tank, tariff history, category memberships) — bundled sample CSVs copied to app output.
- End-to-end render test: import creates meters + consumption; overview/meters/trends/
  import/admin pages all return 200 with KPI cards rendered.

92 tests green (56 Core + 36 integration).

Deferred to polish: dedicated PV & oil/consumable panels, meter-detail page, full admin
CRUD, prev-year trend overlay.

Claude-Session: https://claude.ai/code/session_01WujdMtMJPbxDpDnMeK22rr

src/App/Components/Pages/Admin/EnergyTypes.razor

@@ -0,0 +1,37 @@
+@page "/admin/energy-types"
+@rendermode InteractiveServer
+@inject MeterVault.Infrastructure.Persistence.MeterVaultDbContext Db
+@using Microsoft.EntityFrameworkCore
+
+<PageTitle>MeterVault — Energy types</PageTitle>
+
+<MudText Typo="Typo.h4" Class="mb-4">Energy types</MudText>
+
+@if (_types is null)
+{
+    <MudProgressLinear Indeterminate="true" Color="Color.Primary" />
+}
+else
+{
+    <MudTable Items="_types" Dense="true" Hover="true" Elevation="2">
+        <HeaderContent>
+            <MudTh>Key</MudTh>
+            <MudTh>Display name</MudTh>
+            <MudTh>Base unit</MudTh>
+            <MudTh>Default mode</MudTh>
+        </HeaderContent>
+        <RowTemplate>
+            <MudTd DataLabel="Key">@context.Key</MudTd>
+            <MudTd DataLabel="Display name">@context.DisplayName</MudTd>
+            <MudTd DataLabel="Base unit">@context.BaseUnit</MudTd>
+            <MudTd DataLabel="Default mode">@context.DefaultMode</MudTd>
+        </RowTemplate>
+    </MudTable>
+}
+
+@code {
+    private List<EnergyType>? _types;
+
+    protected override async Task OnInitializedAsync() =>
+        _types = await Db.EnergyTypes.AsNoTracking().OrderBy(t => t.Id).ToListAsync();
+}

src/App/Components/Pages/Admin/Tariffs.razor

@@ -0,0 +1,47 @@
+@page "/admin/tariffs"
+@rendermode InteractiveServer
+@inject MeterVault.Infrastructure.Persistence.MeterVaultDbContext Db
+@using Microsoft.EntityFrameworkCore
+
+<PageTitle>MeterVault — Tariffs</PageTitle>
+
+<MudText Typo="Typo.h4" Class="mb-4">Tariffs</MudText>
+
+@if (_tariffs is null)
+{
+    <MudProgressLinear Indeterminate="true" Color="Color.Primary" />
+}
+else if (_tariffs.Count == 0)
+{
+    <MudAlert Severity="Severity.Info">No tariffs yet. Load the reference data from <MudLink Href="/import">Import</MudLink>.</MudAlert>
+}
+else
+{
+    <MudTable Items="_tariffs" Dense="true" Hover="true" Elevation="2">
+        <HeaderContent>
+            <MudTh>Scope</MudTh>
+            <MudTh>Component</MudTh>
+            <MudTh>Value</MudTh>
+            <MudTh>Unit</MudTh>
+            <MudTh>Valid from</MudTh>
+            <MudTh>Valid to</MudTh>
+        </HeaderContent>
+        <RowTemplate>
+            <MudTd DataLabel="Scope">@context.ScopeType @(context.ScopeId is { } id ? $"#{id}" : "")</MudTd>
+            <MudTd DataLabel="Component">@context.Component</MudTd>
+            <MudTd DataLabel="Value">@Format.Number(context.Value, 4)</MudTd>
+            <MudTd DataLabel="Unit">@context.Unit</MudTd>
+            <MudTd DataLabel="Valid from">@context.ValidFrom.ToString("yyyy-MM-dd")</MudTd>
+            <MudTd DataLabel="Valid to">@(context.ValidTo?.ToString("yyyy-MM-dd") ?? "open")</MudTd>
+        </RowTemplate>
+    </MudTable>
+}
+
+@code {
+    private List<Tariff>? _tariffs;
+
+    protected override async Task OnInitializedAsync() =>
+        _tariffs = await Db.Tariffs.AsNoTracking()
+            .OrderBy(t => t.Component).ThenBy(t => t.ValidFrom)
+            .ToListAsync();
+}