Audit und Laufbelege: Tageswerte je Agent und Einheit, Monatsarchiv statt Loeschen (#700)

Nach der Vorgabe vom 2026-09-22 (so wenig loeschen wie moeglich): Laeufe
aelter als hotDays (Vorgabe 180, 0 = alles bleibt) wandern aus AuditLog und
RunReceipts in Archive/audit-JJJJ-MM.db - kopiert und entfernt in einer
Transaktion, Zeilen-IDs bleiben, spaeter dazugekommene Spalten werden im
Archiv ergaenzt. Vorher wird jeder Tag in RunDaily verdichtet (Laeufe,
Fehlschlaege, Schrittgrenze, Tokens, Kosten, Werkzeugaufrufe, Fehler,
Verweigert, Freigaben) mit der Einheit des Agenten; die Tageswerte bleiben.
Nachschlagen eines Laufs findet ihn auch im Archiv. API /usage/days,
/usage/archive; Karte 'Tageswerte' in der Verbrauchsansicht.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/ClawdDotNet.Core/Audit/SqliteAuditRepository.cs

@@ -83,22 +83,72 @@ public sealed class SqliteAuditRepository : IAuditRepository
 
     public async Task<IReadOnlyList<AuditEntry>> ListForRunAsync(string runId, CancellationToken ct)
     {
-        await using var conn = await _storage.OpenConnectionAsync(ct);
-        using var cmd = conn.CreateCommand();
-        cmd.CommandText = "SELECT " + AuditColumns + " FROM AuditLog WHERE RunId = @runId ORDER BY Id";
-        cmd.Parameters.AddWithValue("@runId", runId);
-        return await ReadEntriesAsync(cmd, ct);
+        await using (var conn = await _storage.OpenConnectionAsync(ct))
+        {
+            using var cmd = conn.CreateCommand();
+            cmd.CommandText = "SELECT " + AuditColumns + " FROM AuditLog WHERE RunId = @runId ORDER BY Id";
+            cmd.Parameters.AddWithValue("@runId", runId);
+            var hot = await ReadEntriesAsync(cmd, ct);
+            if (hot.Count > 0)
+                return hot;
+        }
+
+        // #700: an older run moved to the archive — it is still evidence and still found.
+        foreach (var archive in ArchiveConnections())
+            await using (archive)
+            {
+                using var cmd = archive.CreateCommand();
+                cmd.CommandText = "SELECT " + AuditColumns + " FROM AuditLog WHERE RunId = @runId ORDER BY Id";
+                cmd.Parameters.AddWithValue("@runId", runId);
+                var found = await ReadEntriesAsync(cmd, ct);
+                if (found.Count > 0)
+                    return found;
+            }
+        return [];
     }
 
     public async Task<RunReceipt?> GetReceiptForRunAsync(string runId, CancellationToken ct)
     {
-        await using var conn = await _storage.OpenConnectionAsync(ct);
-        using var cmd = conn.CreateCommand();
-        cmd.CommandText = "SELECT " + ReceiptColumns + " FROM RunReceipts WHERE RunId = @runId ORDER BY Id DESC LIMIT 1";
-        cmd.Parameters.AddWithValue("@runId", runId);
+        await using (var conn = await _storage.OpenConnectionAsync(ct))
+        {
+            using var cmd = conn.CreateCommand();
+            cmd.CommandText = "SELECT " + ReceiptColumns + " FROM RunReceipts WHERE RunId = @runId ORDER BY Id DESC LIMIT 1";
+            cmd.Parameters.AddWithValue("@runId", runId);
+            await using var reader = await cmd.ExecuteReaderAsync(ct);
+            if (await reader.ReadAsync(ct))
+                return ReadReceipt(reader);
+        }
 
-        await using var reader = await cmd.ExecuteReaderAsync(ct);
-        return await reader.ReadAsync(ct) ? ReadReceipt(reader) : null;
+        foreach (var archive in ArchiveConnections())
+            await using (archive)
+            {
+                using var cmd = archive.CreateCommand();
+                cmd.CommandText = "SELECT " + ReceiptColumns + " FROM RunReceipts WHERE RunId = @runId ORDER BY Id DESC LIMIT 1";
+                cmd.Parameters.AddWithValue("@runId", runId);
+                await using var reader = await cmd.ExecuteReaderAsync(ct);
+                if (await reader.ReadAsync(ct))
+                    return ReadReceipt(reader);
+            }
+        return null;
+    }
+
+    /// <summary>
+    /// #700: The month archives, newest first, opened read-only one at a time. A lookup by run
+    /// is rare and asks for one run — opening a few small files for it is cheap.
+    /// </summary>
+    private IEnumerable<SqliteConnection> ArchiveConnections()
+    {
+        foreach (var file in AuditArchive.FilesIn(AuditArchive.ArchiveDirectoryOf(_storage)))
+        {
+            var connection = new SqliteConnection(new SqliteConnectionStringBuilder
+            {
+                DataSource = Path.Combine(AuditArchive.ArchiveDirectoryOf(_storage), file.FileName),
+                Mode = SqliteOpenMode.ReadOnly,
+                Pooling = false
+            }.ToString());
+            connection.Open();
+            yield return connection;
+        }
     }
 
     public async Task<IReadOnlyList<RunReceipt>> ListReceiptsAsync(DateTime fromUtc, DateTime toUtc, int limit, CancellationToken ct)