PR H: log bank-statement imports via ILogger<FileService>

FileService.ImportAccountStatementFile now emits Information on the
file being processed and on each account's import count, Warning on
mandator-mismatch skips, and Error on vendor-parser failures. UI-facing
MessageDataset behaviour is unchanged.

Pulls Microsoft.Extensions.Logging.Abstractions into the Services
project; FileServiceTestShould uses NullLogger<FileService>.Instance.

Rest of item 18 (repository logging, MatchOpenBankTransactions
summary) tracked as a follow-up.

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

IMPROVEMENT_PLAN.md

@@ -103,3 +103,4 @@ Analysis and phased plan produced 2026-07-02. See conversation history for full
 - **PR F** — Phase 3 item 21: precomputed dictionaries in `ViewService` to eliminate O(N·M) `Single(...)` scans and per-account transaction filtering.
 - **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.

Schaad.Accounting.Services/FileService.cs

@@ -2,6 +2,7 @@ using System.Collections.Generic;
 using System.IO.Compression;
 using System.Linq;
 using System.Text;
+using Microsoft.Extensions.Logging;
 using Schaad.Accounting.Datasets;
 using Schaad.Accounting.Interfaces;
 using Schaad.Finance.Api;
@@ -17,6 +18,7 @@ namespace Schaad.Accounting.Services
         private readonly ISettingsService settingsService;
         private readonly IAccountStatementService accountStatementService;
         private readonly ICreditCardStatementService creditCardStatementService;
+        private readonly ILogger<FileService> logger;
 
         public FileService(
             ISettingsService settingsService,
@@ -24,7 +26,8 @@ namespace Schaad.Accounting.Services
             ITransactionRepository transactionsRepository,
             IBankTransactionRepository bankTransactionRepository,
             IAccountStatementService accountStatementService,
-            ICreditCardStatementService creditCardStatementService)
+            ICreditCardStatementService creditCardStatementService,
+            ILogger<FileService> logger)
         {
             this.settingsService = settingsService;
             this.accountRepository = accountRepository;
@@ -32,6 +35,7 @@ namespace Schaad.Accounting.Services
             this.bankTransactionRepository = bankTransactionRepository;
             this.accountStatementService = accountStatementService;
             this.creditCardStatementService = creditCardStatementService;
+            this.logger = logger;
         }
 
         public string Backup()
@@ -46,6 +50,8 @@ namespace Schaad.Accounting.Services
         // http://www.mikesdotnetting.com/article/288/asp-net-5-uploading-files-with-asp-net-mvc-6
         public IReadOnlyList<MessageDataset> ImportAccountStatementFile(string filePath)
         {
+            logger.LogInformation("Importing account statement file {FilePath}", filePath);
+
             var messages = new List<MessageDataset>();
             var accountStatementResults = accountStatementService.ReadFile(filePath, Encoding.UTF8);
 
@@ -56,6 +62,7 @@ namespace Schaad.Accounting.Services
 
                 if (accountStatementResult.IsSuccess == false)
                 {
+                    logger.LogError("Statement parse failed for account {AccountNumber}: {Error}", account.AccountNumber, accountStatementResult.Error);
                     messages.Add(new MessageDataset($"Account {account.AccountNumber} NICHT importiert: {accountStatementResult.Error}", MessageStatus.Error));
                 }
 
@@ -87,6 +94,9 @@ namespace Schaad.Accounting.Services
                     var count = bankTransactionRepository.SaveBankTransactionList(account.AccountNumber, transactionsThisYear);
                     accountRepository.SaveBankAccountBalance(account.AccountNumber, (decimal)account.EndBalance.Value);
 
+                    logger.LogInformation("Imported {Imported} of {Total} transactions for account {AccountNumber}",
+                        count, account.Transactions.Count, account.AccountNumber);
+
                     var status = count == account.Transactions.Count ? MessageStatus.Success : MessageStatus.Info;
                     message.Add($"{count} von {account.Transactions.Count} Transaktion(en) importiert.", status);
 
@@ -99,6 +109,8 @@ namespace Schaad.Accounting.Services
                 }
                 else
                 {
+                    logger.LogWarning("Skipping account {AccountNumber}: not part of the currently selected mandator ({Skipped} transactions ignored)",
+                        account.AccountNumber, account.Transactions.Count);
                     message.Add($"Falscher Mandant: {account.Transactions.Count} Transaktion(en) nicht importiert.", MessageStatus.Warning);
                 }
             }

Schaad.Accounting.Services/Schaad.Accounting.Services.csproj

@@ -6,6 +6,7 @@
 
   <ItemGroup>
     <PackageReference Include="FreeSpire.PDF" Version="10.2.0" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="10.0.9" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Schaad.Accounting.Common\Schaad.Accounting.Common.csproj" />

Schaad.Accounting.Tests/FileServiceTestShould.cs

@@ -1,4 +1,5 @@
 using System.Text;
+using Microsoft.Extensions.Logging.Abstractions;
 using NSubstitute;
 using Schaad.Accounting.Interfaces;
 using Schaad.Accounting.Models;
@@ -26,7 +27,7 @@ public class FileServiceTestShould
 
     private FileService BuildService() => new(
         settingsService, accountRepo, transactionRepo, bankTransactionRepo,
-        accountStatementService, creditCardStatementService);
+        accountStatementService, creditCardStatementService, NullLogger<FileService>.Instance);
 
     [Fact]
     public void EmitHeaderRowAndRunningBalanceWhenExportingTransactionsCsv()