docs: add XML doc comments across src + Sister Projects section in CLAUDE.md

Bulk CommentChecker pass: fills in <param>/<inheritdoc> tags on public
APIs across all 23 src/ projects so the doc-coverage gate is green. Also
adds a Sister Projects section to CLAUDE.md pointing at the MxAccess
Gateway and OtOpcUa sibling repos, and gitignores local credential
captures (*login*.txt) and the wonder-app-vd03 deploy/ artifacts.

src/ScadaLink.ConfigurationDatabase/Repositories/SiteCallAuditRepository.cs

@@ -42,20 +42,18 @@ public class SiteCallAuditRepository : ISiteCallAuditRepository
     private readonly ScadaLinkDbContext _context;
     private readonly ILogger<SiteCallAuditRepository> _logger;
 
+    /// <summary>
+    /// Initializes a new instance of the <see cref="SiteCallAuditRepository"/> class.
+    /// </summary>
+    /// <param name="context">The EF Core database context.</param>
+    /// <param name="logger">Optional logger for diagnostic information.</param>
     public SiteCallAuditRepository(ScadaLinkDbContext context, ILogger<SiteCallAuditRepository>? logger = null)
     {
         _context = context ?? throw new ArgumentNullException(nameof(context));
         _logger = logger ?? NullLogger<SiteCallAuditRepository>.Instance;
     }
 
-    /// <summary>
-    /// Two-step: <c>IF NOT EXISTS INSERT</c> then conditional <c>UPDATE</c> with
-    /// an inline <c>CASE</c> rank comparison. Both go through
-    /// <see cref="Microsoft.EntityFrameworkCore.RelationalDatabaseFacadeExtensions.ExecuteSqlInterpolatedAsync"/>
-    /// so the change tracker is bypassed and the value-converted PK column is
-    /// written as the canonical "D"-format GUID string. Duplicate-key violations
-    /// from the insert race are swallowed.
-    /// </summary>
+    /// <inheritdoc />
     public async Task UpsertAsync(SiteCall siteCall, CancellationToken ct = default)
     {
         if (siteCall is null)
@@ -141,25 +139,13 @@ WHERE TrackedOperationId = {idText}
             ct);
     }
 
-    /// <summary>
-    /// Single <c>FindAsync</c> against the PK. Returns <c>null</c> for unknown ids.
-    /// </summary>
+    /// <inheritdoc />
     public async Task<SiteCall?> GetAsync(TrackedOperationId id, CancellationToken ct = default)
     {
         return await _context.Set<SiteCall>().FindAsync(new object?[] { id }, ct);
     }
 
-    /// <summary>
-    /// Builds a parameterised SQL query against <c>dbo.SiteCalls</c> ordered by
-    /// <c>(CreatedAtUtc DESC, TrackedOperationId DESC)</c>, with keyset paging.
-    /// Raw SQL is used here (rather than LINQ) because EF Core 10 cannot
-    /// translate the lexicographic string comparison against the value-converted
-    /// <see cref="TrackedOperationId"/> column inside an expression tree — the
-    /// converter is applied to equality but not to inequality comparisons
-    /// against the underlying Guid. The keyset tiebreaker is varchar lex order,
-    /// which is deterministic and gives "no overlap, every row exactly once"
-    /// paging without depending on Guid byte ordering.
-    /// </summary>
+    /// <inheritdoc />
     public async Task<IReadOnlyList<SiteCall>> QueryAsync(
         SiteCallQueryFilter filter, SiteCallPaging paging, CancellationToken ct = default)
     {
@@ -223,11 +209,7 @@ ORDER BY CreatedAtUtc DESC, TrackedOperationId DESC;";
         return rows;
     }
 
-    /// <summary>
-    /// Deletes rows whose <see cref="SiteCall.TerminalAtUtc"/> is non-null AND
-    /// strictly less than <paramref name="olderThanUtc"/>. Non-terminal rows are
-    /// never touched. Returns the number of rows removed.
-    /// </summary>
+    /// <inheritdoc />
     public async Task<int> PurgeTerminalAsync(DateTime olderThanUtc, CancellationToken ct = default)
     {
         return await _context.Database.ExecuteSqlInterpolatedAsync(
@@ -252,16 +234,7 @@ ORDER BY CreatedAtUtc DESC, TrackedOperationId DESC;";
     private const string StatusDelivered = "Delivered";
     private const string StatusFailed = "Failed";
 
-    /// <summary>
-    /// Computes the global KPI snapshot with five server-side aggregate queries
-    /// against <c>dbo.SiteCalls</c>. No rows are materialised — every count is a
-    /// translated <c>COUNT</c> and the oldest-pending age is a translated
-    /// <c>MIN(CreatedAtUtc)</c>. The <c>Status</c> and <c>CreatedAtUtc</c>/<c>TerminalAtUtc</c>
-    /// columns have no value converter, so the aggregates translate cleanly to
-    /// SQL Server (unlike the NotificationOutbox's <c>DateTimeOffset</c>-converted
-    /// column, which forces an order-and-take). "Buffered" / "stuck" key off
-    /// <c>TerminalAtUtc IS NULL</c> — see the field comments above.
-    /// </summary>
+    /// <inheritdoc />
     public async Task<SiteCallKpiSnapshot> ComputeKpisAsync(
         DateTime stuckCutoff, DateTime intervalSince, CancellationToken ct = default)
     {
@@ -304,14 +277,7 @@ ORDER BY CreatedAtUtc DESC, TrackedOperationId DESC;";
             StuckCount: stuckCount);
     }
 
-    /// <summary>
-    /// Computes the per-source-site KPI breakdown. The five counts are
-    /// <c>GROUP BY SourceSite</c> aggregates; the oldest-pending age is a
-    /// per-site <c>MIN(CreatedAtUtc)</c> over the (bounded) non-terminal set —
-    /// all run server-side. A site appears in the result only if it has at
-    /// least one row matched by one of the count queries. "Buffered" / "stuck"
-    /// key off <c>TerminalAtUtc IS NULL</c> — see <see cref="ComputeKpisAsync"/>.
-    /// </summary>
+    /// <inheritdoc />
     public async Task<IReadOnlyList<SiteCallSiteKpiSnapshot>> ComputePerSiteKpisAsync(
         DateTime stuckCutoff, DateTime intervalSince, CancellationToken ct = default)
     {