feat(localdb): rewire SiteEventLogger onto the consolidated site database

Completes Task 5a of the LocalDb Phase 1 adoption plan. The GUID-id half landed
with Task 2 (727fa48c) because leaving it out would have committed a writer that
could not satisfy site_events.id NOT NULL; this is the connection half, which
was blocked on Task 3.

SiteEventLogger owned a SqliteConnection built from SiteEventLogOptions
.DatabasePath. It now takes ILocalDb and gets that connection from
CreateConnection() - already open, pragma-configured, and carrying the
zb_hlc_next() UDF that site_events' capture triggers call. It still owns and
disposes the connection; WithConnection's signature and locking semantics are
untouched, so EventLogQueryService and EventLogPurgeService are unaffected.

The connectionStringOverride seam is deleted rather than preserved. site_events
is a replicated table, so a raw connection lacks the UDF and fails closed on
every insert - an override could only produce a logger that cannot write. It had
no callers outside this class (the connectionStringOverride hits elsewhere in the
tree belong to SqliteAuditWriter, a different type).

Tests: a shared TestLocalDb helper gives each fixture a real ILocalDb over a temp
file. Real rather than stubbed on purpose - a stub handing back a bare
SqliteConnection would pass today and fail closed the moment the table is
registered, which is exactly the silent-wiring failure mode this family has hit
three times. ServiceWiringTests' DI path also needed AddZbLocalDb, mirroring
SiteServiceRegistration.

Verified: build 0 warnings; SiteEventLogging 70/70, Host 294/294,
SiteRuntime 530/530.

Claude-Session: https://claude.ai/code/session_01BL2Vu1ESDQ9SCN4gVKkdts

tests/ZB.MOM.WW.ScadaBridge.SiteEventLogging.Tests/EventLogQueryServiceTests.cs

@@ -8,6 +8,7 @@ public class EventLogQueryServiceTests : IDisposable
 {
     private readonly SiteEventLogger _eventLogger;
     private readonly EventLogQueryService _queryService;
+    private readonly TestLocalDb _localDb;
     private readonly string _dbPath;
 
     public EventLogQueryServiceTests()
@@ -18,7 +19,8 @@ public class EventLogQueryServiceTests : IDisposable
             DatabasePath = _dbPath,
             QueryPageSize = 500
         });
-        _eventLogger = new SiteEventLogger(options, NullLogger<SiteEventLogger>.Instance);
+        _localDb = TestLocalDb.Create(_dbPath);
+        _eventLogger = new SiteEventLogger(options, NullLogger<SiteEventLogger>.Instance, _localDb.Db);
         _queryService = new EventLogQueryService(
             _eventLogger,
             options,
@@ -28,7 +30,9 @@ public class EventLogQueryServiceTests : IDisposable
     public void Dispose()
     {
         _eventLogger.Dispose();
-        if (File.Exists(_dbPath)) File.Delete(_dbPath);
+        _localDb.Dispose();
+        TestLocalDb.DeleteFiles(_dbPath);
+        GC.SuppressFinalize(this);
     }
 
     private async Task SeedEvents()
@@ -367,7 +371,8 @@ public class EventLogQueryServiceTests : IDisposable
             QueryPageSize = 500,
             MaxQueryPageSize = 3,
         });
-        using var logger = new SiteEventLogger(options, NullLogger<SiteEventLogger>.Instance);
+        using var localDb = TestLocalDb.Create(dbPath);
+        using var logger = new SiteEventLogger(options, NullLogger<SiteEventLogger>.Instance, localDb.Db);
         var query = new EventLogQueryService(logger, options, NullLogger<EventLogQueryService>.Instance);
 
         try
@@ -391,7 +396,8 @@ public class EventLogQueryServiceTests : IDisposable
         finally
         {
             logger.Dispose();
-            if (File.Exists(dbPath)) File.Delete(dbPath);
+            localDb.Dispose();
+            TestLocalDb.DeleteFiles(dbPath);
         }
     }
 }