PR I: move service interfaces out of Common

IViewService, IFileService, and IChartService move from
Schaad.Accounting.Common/Interfaces/ to
Schaad.Accounting.Services/Interfaces/. Namespaces are unchanged, so
no consumer needs a using update. Common's vendor <Reference
Include="Schaad.Finance.Api"> can be dropped, matching Common's
documented role as the shared models/DTOs/interfaces layer.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

IMPROVEMENT_PLAN.md

@@ -104,3 +104,4 @@ Analysis and phased plan produced 2026-07-02. See conversation history for full
 - **Item 19 (async I/O)** — deferred. After PR D, each XML file is loaded at most once per SignalR circuit, and this app is single-user local Blazor Server. Converting every repository/service method to async would touch ~40 files for negligible user-visible benefit and real regression risk. Revisit if the app is ever hosted for multiple concurrent users.
 - **PR G** — Phase 4 items 23 + 24: `Schaad.Accounting.Tests` xUnit + NSubstitute + Shouldly project. Adopts the `xxxTestShould.DoThisWhenThat` naming convention with Shouldly assertions (no xUnit `Assert.*`). Covers `ViewService`, `TransactionRepository`, `Formatting`, `RepositoryCache`, `AccountRepository`, `ChartService`, and `FileService.GetTransactionListCsv` — 38 tests locking in the earlier PRs' behavior. Note: originally shipped as three separate commits (initial project, expanded coverage, Shouldly + naming conversion) and later squashed into one commit at the user's request.
 - **PR H** — Phase 2 item 18 (first slice): add `ILogger<FileService>` to `FileService.ImportAccountStatementFile` so bank-statement imports emit `Information` for the file being processed and each account's import count, `Warning` when an account is skipped because it belongs to a different mandator, and `Error` when the vendor parser reports a failure. Rest of the logging (BaseRepository save failures, MatchOpenBankTransactions summary) tracked as a follow-up because it requires threading loggers through all seven repositories.
+- **PR I** — Phase 2 item 12: move the service interfaces (`IViewService`, `IFileService`, `IChartService`) from `Schaad.Accounting.Common` into `Schaad.Accounting.Services/Interfaces/`. Namespaces are unchanged (`Schaad.Accounting.Interfaces`), so no consumer needs a `using` update. Drops the `Schaad.Finance.Api` `<Reference>` from `Common.csproj` — Common is now vendor-free and matches its documented role as the "shared models, DTOs, interfaces" layer.

Schaad.Accounting.Common/Schaad.Accounting.Common.csproj

@@ -4,9 +4,4 @@
     <TargetFramework>net9.0</TargetFramework>
     <RootNamespace>Schaad.Accounting</RootNamespace>
   </PropertyGroup>
-  <ItemGroup>
-    <Reference Include="Schaad.Finance.Api">
-      <HintPath>..\dlls\Schaad.Finance.Api.dll</HintPath>
-    </Reference>
-  </ItemGroup>
 </Project>