M4 Ledger-Service fuer erste App-Abfragen ergaenzen

- zentrale Ledger-Abfragen fuer Tenant- und Teilnehmer-Summen bauen
- letzte Buchungen und Einzelteilnehmer ueber app/ledger.php lesbar machen
- Service-Check und M4-Doku ergaenzen

app/ledger.php

@@ -0,0 +1,281 @@
+<?php
+
+declare(strict_types=1);
+
+require_once __DIR__ . '/bootstrap.php';
+
+/**
+ * @return list<string>
+ */
+function ledger_normalize_email_norms(array $emails): array
+{
+    $normalized = [];
+    foreach ($emails as $email) {
+        $emailNorm = strtolower(trim((string)$email));
+        if ($emailNorm !== '') {
+            $normalized[$emailNorm] = true;
+        }
+    }
+
+    return array_keys($normalized);
+}
+
+/**
+ * @return list<int>
+ */
+function ledger_normalize_ids(array $ids): array
+{
+    $normalized = [];
+    foreach ($ids as $id) {
+        $id = (int)$id;
+        if ($id > 0) {
+            $normalized[$id] = true;
+        }
+    }
+
+    return array_keys($normalized);
+}
+
+function ledger_current_year(): int
+{
+    return (int)date('Y');
+}
+
+/**
+ * @return array{total_payments_cents: int, total_costs_cents: int, total_marks: int, balance_cents: int, year_payments_cents: int, year_costs_cents: int, year_marks: int}
+ */
+function ledger_empty_totals(): array
+{
+    return [
+        'total_payments_cents' => 0,
+        'total_costs_cents' => 0,
+        'total_marks' => 0,
+        'balance_cents' => 0,
+        'year_payments_cents' => 0,
+        'year_costs_cents' => 0,
+        'year_marks' => 0,
+    ];
+}
+
+/**
+ * @return array{total_payments_cents: int, total_costs_cents: int, total_marks: int, balance_cents: int, year_payments_cents: int, year_costs_cents: int, year_marks: int}
+ */
+function ledger_fetch_tenant_totals(PDO $pdo, int $tenantId, ?int $year = null): array
+{
+    $year = $year ?? ledger_current_year();
+    $stmt = $pdo->prepare(
+        "SELECT
+            COALESCE(SUM(CASE WHEN type = 'payment' THEN amount_cents ELSE 0 END), 0) AS total_payments_cents,
+            COALESCE(SUM(CASE WHEN type = 'consumption' THEN -amount_cents ELSE 0 END), 0) AS total_costs_cents,
+            COALESCE(SUM(CASE WHEN type = 'consumption' THEN marks_count ELSE 0 END), 0) AS total_marks,
+            COALESCE(SUM(amount_cents), 0) AS balance_cents,
+            COALESCE(SUM(CASE WHEN type = 'payment' AND YEAR(booked_at) = ? THEN amount_cents ELSE 0 END), 0) AS year_payments_cents,
+            COALESCE(SUM(CASE WHEN type = 'consumption' AND YEAR(booked_at) = ? THEN -amount_cents ELSE 0 END), 0) AS year_costs_cents,
+            COALESCE(SUM(CASE WHEN type = 'consumption' AND YEAR(booked_at) = ? THEN marks_count ELSE 0 END), 0) AS year_marks
+         FROM ledger_entries
+         WHERE tenant_id = ?
+           AND voided_at IS NULL"
+    );
+    $stmt->execute([$year, $year, $year, $tenantId]);
+    $row = $stmt->fetch();
+
+    if ($row === false) {
+        return ledger_empty_totals();
+    }
+
+    return [
+        'total_payments_cents' => (int)$row['total_payments_cents'],
+        'total_costs_cents' => (int)$row['total_costs_cents'],
+        'total_marks' => (int)$row['total_marks'],
+        'balance_cents' => (int)$row['balance_cents'],
+        'year_payments_cents' => (int)$row['year_payments_cents'],
+        'year_costs_cents' => (int)$row['year_costs_cents'],
+        'year_marks' => (int)$row['year_marks'],
+    ];
+}
+
+/**
+ * Options:
+ * - year: int
+ * - active_only: bool|null
+ * - participant_ids: list<int>
+ * - email_norms: list<string>
+ *
+ * @return list<array{participant_id: int, tenant_id: int, display_name: string, email: ?string, email_norm: ?string, paypal_name: ?string, active: bool, total_payments_cents: int, total_costs_cents: int, total_marks: int, balance_cents: int, year_payments_cents: int, year_costs_cents: int, year_marks: int}>
+ */
+function ledger_fetch_participant_summaries(PDO $pdo, int $tenantId, array $options = []): array
+{
+    $year = isset($options['year']) ? (int)$options['year'] : ledger_current_year();
+    $where = ['p.tenant_id = ?'];
+    $params = [$year, $year, $year, $tenantId];
+
+    if (array_key_exists('active_only', $options) && $options['active_only'] !== null) {
+        $where[] = 'p.active = ?';
+        $params[] = $options['active_only'] ? 1 : 0;
+    }
+
+    if (array_key_exists('participant_ids', $options)) {
+        $participantIds = is_array($options['participant_ids'])
+            ? ledger_normalize_ids($options['participant_ids'])
+            : [];
+        if ($participantIds === []) {
+            return [];
+        }
+        $where[] = 'p.id IN (' . implode(',', array_fill(0, count($participantIds), '?')) . ')';
+        array_push($params, ...$participantIds);
+    }
+
+    if (array_key_exists('email_norms', $options)) {
+        $emailNorms = is_array($options['email_norms'])
+            ? ledger_normalize_email_norms($options['email_norms'])
+            : [];
+        if ($emailNorms === []) {
+            return [];
+        }
+        $where[] = 'p.email_norm IN (' . implode(',', array_fill(0, count($emailNorms), '?')) . ')';
+        array_push($params, ...$emailNorms);
+    }
+
+    $sql = "
+        SELECT
+            p.id AS participant_id,
+            p.tenant_id,
+            p.display_name,
+            p.email,
+            p.email_norm,
+            p.paypal_name,
+            p.active,
+            COALESCE(SUM(CASE WHEN le.type = 'payment' THEN le.amount_cents ELSE 0 END), 0) AS total_payments_cents,
+            COALESCE(SUM(CASE WHEN le.type = 'consumption' THEN -le.amount_cents ELSE 0 END), 0) AS total_costs_cents,
+            COALESCE(SUM(CASE WHEN le.type = 'consumption' THEN le.marks_count ELSE 0 END), 0) AS total_marks,
+            COALESCE(SUM(le.amount_cents), 0) AS balance_cents,
+            COALESCE(SUM(CASE WHEN le.type = 'payment' AND YEAR(le.booked_at) = ? THEN le.amount_cents ELSE 0 END), 0) AS year_payments_cents,
+            COALESCE(SUM(CASE WHEN le.type = 'consumption' AND YEAR(le.booked_at) = ? THEN -le.amount_cents ELSE 0 END), 0) AS year_costs_cents,
+            COALESCE(SUM(CASE WHEN le.type = 'consumption' AND YEAR(le.booked_at) = ? THEN le.marks_count ELSE 0 END), 0) AS year_marks
+        FROM participants p
+        LEFT JOIN ledger_entries le
+          ON le.tenant_id = p.tenant_id
+         AND le.participant_id = p.id
+         AND le.voided_at IS NULL
+        WHERE " . implode(' AND ', $where) . "
+        GROUP BY p.id, p.tenant_id, p.display_name, p.email, p.email_norm, p.paypal_name, p.active
+        ORDER BY p.display_name, p.id";
+
+    $stmt = $pdo->prepare($sql);
+    $stmt->execute($params);
+
+    $summaries = [];
+    while ($row = $stmt->fetch()) {
+        $summaries[] = [
+            'participant_id' => (int)$row['participant_id'],
+            'tenant_id' => (int)$row['tenant_id'],
+            'display_name' => (string)$row['display_name'],
+            'email' => $row['email'] !== null ? (string)$row['email'] : null,
+            'email_norm' => $row['email_norm'] !== null ? (string)$row['email_norm'] : null,
+            'paypal_name' => $row['paypal_name'] !== null ? (string)$row['paypal_name'] : null,
+            'active' => (int)$row['active'] === 1,
+            'total_payments_cents' => (int)$row['total_payments_cents'],
+            'total_costs_cents' => (int)$row['total_costs_cents'],
+            'total_marks' => (int)$row['total_marks'],
+            'balance_cents' => (int)$row['balance_cents'],
+            'year_payments_cents' => (int)$row['year_payments_cents'],
+            'year_costs_cents' => (int)$row['year_costs_cents'],
+            'year_marks' => (int)$row['year_marks'],
+        ];
+    }
+
+    return $summaries;
+}
+
+/**
+ * @return array{participant_id: int, tenant_id: int, display_name: string, email: ?string, email_norm: ?string, paypal_name: ?string, active: bool, total_payments_cents: int, total_costs_cents: int, total_marks: int, balance_cents: int, year_payments_cents: int, year_costs_cents: int, year_marks: int}|null
+ */
+function ledger_fetch_participant_summary(PDO $pdo, int $tenantId, int $participantId, ?int $year = null): ?array
+{
+    $summaries = ledger_fetch_participant_summaries($pdo, $tenantId, [
+        'participant_ids' => [$participantId],
+        'year' => $year ?? ledger_current_year(),
+    ]);
+
+    return $summaries[0] ?? null;
+}
+
+/**
+ * Options:
+ * - participant_id: int
+ * - type: string
+ * - include_voided: bool
+ * - limit: int
+ *
+ * @return list<array{id: int, tenant_id: int, participant_id: int, display_name: string, type: string, amount_cents: int, marks_count: ?int, unit_price_cents: ?int, booked_at: string, source: string, note: ?string, legacy_table: ?string, legacy_id: ?int, voided_at: ?string}>
+ */
+function ledger_fetch_recent_entries(PDO $pdo, int $tenantId, array $options = []): array
+{
+    $limit = isset($options['limit']) ? (int)$options['limit'] : 100;
+    $limit = max(1, min($limit, 500));
+    $where = ['le.tenant_id = ?'];
+    $params = [$tenantId];
+
+    if (empty($options['include_voided'])) {
+        $where[] = 'le.voided_at IS NULL';
+    }
+
+    if (!empty($options['participant_id'])) {
+        $where[] = 'le.participant_id = ?';
+        $params[] = (int)$options['participant_id'];
+    }
+
+    if (!empty($options['type'])) {
+        $where[] = 'le.type = ?';
+        $params[] = trim((string)$options['type']);
+    }
+
+    $sql = "
+        SELECT
+            le.id,
+            le.tenant_id,
+            le.participant_id,
+            p.display_name,
+            le.type,
+            le.amount_cents,
+            le.marks_count,
+            le.unit_price_cents,
+            le.booked_at,
+            le.source,
+            le.note,
+            le.legacy_table,
+            le.legacy_id,
+            le.voided_at
+        FROM ledger_entries le
+        JOIN participants p
+          ON p.tenant_id = le.tenant_id
+         AND p.id = le.participant_id
+        WHERE " . implode(' AND ', $where) . "
+        ORDER BY le.booked_at DESC, le.id DESC
+        LIMIT {$limit}";
+
+    $stmt = $pdo->prepare($sql);
+    $stmt->execute($params);
+
+    $entries = [];
+    while ($row = $stmt->fetch()) {
+        $entries[] = [
+            'id' => (int)$row['id'],
+            'tenant_id' => (int)$row['tenant_id'],
+            'participant_id' => (int)$row['participant_id'],
+            'display_name' => (string)$row['display_name'],
+            'type' => (string)$row['type'],
+            'amount_cents' => (int)$row['amount_cents'],
+            'marks_count' => $row['marks_count'] !== null ? (int)$row['marks_count'] : null,
+            'unit_price_cents' => $row['unit_price_cents'] !== null ? (int)$row['unit_price_cents'] : null,
+            'booked_at' => (string)$row['booked_at'],
+            'source' => (string)$row['source'],
+            'note' => $row['note'] !== null ? (string)$row['note'] : null,
+            'legacy_table' => $row['legacy_table'] !== null ? (string)$row['legacy_table'] : null,
+            'legacy_id' => $row['legacy_id'] !== null ? (int)$row['legacy_id'] : null,
+            'voided_at' => $row['voided_at'] !== null ? (string)$row['voided_at'] : null,
+        ];
+    }
+
+    return $entries;
+}

docs/m4-data-migration.md

@@ -5,7 +5,8 @@ Stand: 2026-07-13
 M4 uebernimmt die finanznahen Legacy-Buchungen additiv in das neue
 tenant-sichere Ledger-Modell. Die bestehenden Legacy-Seiten lesen und schreiben
 weiterhin die bisherigen `kl_*`-Tabellen; das Ledger dient zunaechst als
-vergleichbare, pruefbare Zielstruktur.
+vergleichbare, pruefbare Zielstruktur. Erste App-Abfragen koennen nun ueber
+einen zentralen Ledger-Service gegen `ledger_entries` laufen.
 
 ## Ziel
 
@@ -40,6 +41,13 @@ Ergaenzende Skripte:
 ```text
 scripts/backfill-ledger-entries.php
 scripts/check-m4-ledger-migration.php
+scripts/check-m4-ledger-service.php
+```
+
+Ergaenzende App-Dateien:
+
+```text
+app/ledger.php
 ```
 
 Ausgefuehrter Dev-Stand:
@@ -48,6 +56,8 @@ Ausgefuehrter Dev-Stand:
 - 9 Legacy-Einzahlungen wurden als `payment` gespiegelt.
 - 12 Legacy-Kaffeeverbrauch-Zeilen wurden als `consumption` gespiegelt.
 - Ein zweiter Backfill-Lauf blieb idempotent und erzeugte keine Dubletten.
+- `app/ledger.php` stellt zentrale Abfragen fuer Tenant-Summen,
+  Teilnehmer-Summen, einzelne Teilnehmer und letzte Buchungen bereit.
 
 ## Abbildungsregeln
 
@@ -111,6 +121,7 @@ nicht aus den `kl_*`-Tabellen geloescht.
 php scripts/backfill-default-tenant.php
 php scripts/backfill-ledger-entries.php
 php scripts/check-m4-ledger-migration.php
+php scripts/check-m4-ledger-service.php
 php scripts/check-golden-master.php
 ```
 
@@ -128,10 +139,15 @@ Installation aus `.local/` verwendet werden.
 - Web-Striche aus `Eintragsart = 2` bleiben als `source = legacy_web`
   erkennbar: erfuellt.
 - Ledger-Summen entsprechen dem Golden Master: erfuellt.
+- Zentrale Ledger-Abfragen liefern dieselben Teilnehmer-Summen wie der Golden
+  Master: erfuellt.
+- Tenant-Summen, aktive Teilnehmer, Einzelteilnehmer und letzte Buchungen sind
+  ueber `app/ledger.php` abrufbar: erfuellt.
 
 ## Aktueller Pruefstatus
 
 - M4 Ledger-Migration: gruen mit 73 Assertions.
+- M4 Ledger-Service: gruen mit 102 Assertions.
 - M3 SaaS-Basis: weiterhin gruen.
 - M3 Tenant-Aufloesung: weiterhin gruen.
 - M3 Passwort/E-Mail: weiterhin gruen.
@@ -143,8 +159,8 @@ Installation aus `.local/` verwendet werden.
 
 ## Noch offen in M4
 
-- Neues Repository/Service fuer Ledger-Abfragen der App-Seiten.
-- Tenant-sichere Dashboard-, Strich-, Einzahlungs- und Listenqueries auf Basis
-  des Ledgers.
+- Erste read-only App-Seite oder Preview auf Basis von `app/ledger.php`.
+- Tenant-sichere Dashboard-, Strich-, Einzahlungs- und Listenqueries schrittweise
+  von Legacy-Tabellen auf das Ledger umstellen.
 - Storno-/Reversal-Modell in der UI statt harter Deletes.
 - Delta-Strategie fuer den finalen Cutover.

docs/saas-umstrukturierungsplan.md

@@ -284,7 +284,7 @@ Uebersicht:
 | M1 | Golden Master | Legacy-Ergebnisse sind als Vergleichsbasis eingefroren; HTTP-Smoke prueft sichere Seiten |
 | M2 | Technisches Fundament | Abgeschlossen: Migrationen, Bootstrap, Session, CSRF-Helper und Legacy-Schreibseitenschutz stehen |
 | M3 | SaaS-Basis | Abgeschlossen: Tenants, User, Registrierung, Login, Rollen, Mail-Links und zentrale Mandantenauswahl funktionieren |
-| M4 | Datenmigration | Gestartet: Ledger-Tabelle, Legacy-Backfill und Paritaetscheck sind umgesetzt |
+| M4 | Datenmigration | Gestartet: Ledger-Tabelle, Legacy-Backfill, Paritaetscheck und Ledger-Service sind umgesetzt |
 | M5 | App-Kern | Dashboard, Striche, Einzahlungen, Mitglieder und Liste laufen |
 | M6 | Betriebsflows | Import, Export, Mail und Jahresprozesse sind auditierbar |
 | M7 | Landingpage | Erste werbliche Seite ist oeffentlich nutzbar; spaetere Ausbaustufen folgen |
@@ -457,12 +457,16 @@ Schritte:
   spiegeln: erster Backfill erledigt.
 - Legacy-IDs speichern: erledigt ueber `legacy_table` und `legacy_id`.
 - Salden gegen Golden-Master vergleichen: Kontrollskript erledigt.
+- Ledger-Service fuer Tenant-Summen, Teilnehmer-Summen und letzte Buchungen:
+  erledigt.
 
 Ergebnis:
 
 - Bestehender Datenbestand kann im neuen Modell abgebildet werden.
 - Saldenparitaet ist ueber `scripts/check-m4-ledger-migration.php`
   nachweisbar.
+- Erste App-Abfragen koennen ueber `app/ledger.php` tenant-sicher aus dem neuen
+  Modell lesen.
 - Dokumentation: `docs/m4-data-migration.md`.
 
 Abhaengigkeiten:

scripts/check-m4-ledger-service.php

@@ -0,0 +1,189 @@
+<?php
+
+declare(strict_types=1);
+
+require __DIR__ . '/dev-db.php';
+require __DIR__ . '/golden-master-data.php';
+require __DIR__ . '/../app/ledger.php';
+
+function m4_service_env(string $name, string $default): string
+{
+    $value = getenv($name);
+    if ($value === false || trim($value) === '') {
+        return $default;
+    }
+
+    return trim($value);
+}
+
+function m4_service_assert_equal(string $label, mixed $expected, mixed $actual, array &$failures, int &$passes): void
+{
+    if ($expected === $actual) {
+        $passes++;
+        echo "PASS {$label}\n";
+        return;
+    }
+
+    $failures[] = "{$label}: expected " . var_export($expected, true) . ', got ' . var_export($actual, true);
+    echo "FAIL {$label}\n";
+}
+
+function m4_service_assert(string $label, bool $condition, array &$failures, int &$passes): void
+{
+    m4_service_assert_equal($label, true, $condition, $failures, $passes);
+}
+
+function m4_service_fetch_tenant_id(PDO $pdo, string $slug): int
+{
+    $stmt = $pdo->prepare('SELECT id FROM tenants WHERE slug = ?');
+    $stmt->execute([$slug]);
+    $tenantId = $stmt->fetchColumn();
+
+    if ($tenantId === false) {
+        throw new RuntimeException("Tenant '{$slug}' not found.");
+    }
+
+    return (int)$tenantId;
+}
+
+/**
+ * @return array{total_payments_cents: int, total_costs_cents: int, total_marks: int, balance_cents: int, year_payments_cents: int, year_costs_cents: int, year_marks: int}
+ */
+function m4_service_totals_from_summaries(array $summaries): array
+{
+    $totals = ledger_empty_totals();
+
+    foreach ($summaries as $summary) {
+        $totals['total_payments_cents'] += (int)$summary['total_payments_cents'];
+        $totals['total_costs_cents'] += (int)$summary['total_costs_cents'];
+        $totals['total_marks'] += (int)$summary['total_marks'];
+        $totals['balance_cents'] += (int)$summary['balance_cents'];
+        $totals['year_payments_cents'] += (int)$summary['year_payments_cents'];
+        $totals['year_costs_cents'] += (int)$summary['year_costs_cents'];
+        $totals['year_marks'] += (int)$summary['year_marks'];
+    }
+
+    return $totals;
+}
+
+$pdo = dev_pdo();
+dev_apply_schema($pdo);
+
+$tenantSlug = m4_service_env('M4_DEFAULT_TENANT_SLUG', m4_service_env('M3_DEFAULT_TENANT_SLUG', 'default'));
+$tenantId = m4_service_fetch_tenant_id($pdo, $tenantSlug);
+$expected = gm_expected_summaries();
+$emails = array_keys($expected);
+$failures = [];
+$passes = 0;
+
+$summaries = ledger_fetch_participant_summaries($pdo, $tenantId, [
+    'email_norms' => $emails,
+    'year' => gm_current_year(),
+]);
+
+$summariesByEmail = [];
+foreach ($summaries as $summary) {
+    if ($summary['email_norm'] !== null) {
+        $summariesByEmail[$summary['email_norm']] = $summary;
+    }
+}
+
+m4_service_assert_equal('ledger service summary count', count($expected), count($summariesByEmail), $failures, $passes);
+
+$keyMap = [
+    'total_payments' => 'total_payments_cents',
+    'total_costs' => 'total_costs_cents',
+    'total_marks' => 'total_marks',
+    'balance' => 'balance_cents',
+    'year_payments' => 'year_payments_cents',
+    'year_costs' => 'year_costs_cents',
+    'year_marks' => 'year_marks',
+];
+
+foreach ($expected as $email => $expectedSummary) {
+    m4_service_assert("ledger service summary exists {$email}", isset($summariesByEmail[$email]), $failures, $passes);
+    if (!isset($summariesByEmail[$email])) {
+        continue;
+    }
+
+    foreach ($keyMap as $expectedKey => $actualKey) {
+        m4_service_assert_equal(
+            "ledger service {$email} {$expectedKey}",
+            $expectedSummary[$expectedKey],
+            $summariesByEmail[$email][$actualKey],
+            $failures,
+            $passes
+        );
+    }
+}
+
+$allSummaries = ledger_fetch_participant_summaries($pdo, $tenantId, [
+    'year' => gm_current_year(),
+]);
+$tenantTotals = ledger_fetch_tenant_totals($pdo, $tenantId, gm_current_year());
+foreach (m4_service_totals_from_summaries($allSummaries) as $key => $value) {
+    m4_service_assert_equal("ledger service tenant total {$key}", $value, $tenantTotals[$key], $failures, $passes);
+}
+
+$stmt = $pdo->prepare('SELECT COUNT(*) FROM participants WHERE tenant_id = ? AND active = 1');
+$stmt->execute([$tenantId]);
+$activeExpectedCount = (int)$stmt->fetchColumn();
+$activeSummaries = ledger_fetch_participant_summaries($pdo, $tenantId, ['active_only' => true]);
+m4_service_assert_equal('ledger service active participant count', $activeExpectedCount, count($activeSummaries), $failures, $passes);
+
+$paypalSummary = $summariesByEmail['gm-paypal@test.local'] ?? null;
+m4_service_assert('ledger service paypal summary is present', $paypalSummary !== null, $failures, $passes);
+if ($paypalSummary !== null) {
+    $singleSummary = ledger_fetch_participant_summary($pdo, $tenantId, $paypalSummary['participant_id'], gm_current_year());
+    m4_service_assert('ledger service single participant summary is present', $singleSummary !== null, $failures, $passes);
+    if ($singleSummary !== null) {
+        m4_service_assert_equal('ledger service single participant email', 'gm-paypal@test.local', $singleSummary['email_norm'], $failures, $passes);
+        m4_service_assert_equal('ledger service single participant balance', 650, $singleSummary['balance_cents'], $failures, $passes);
+    }
+
+    $paypalEntries = ledger_fetch_recent_entries($pdo, $tenantId, [
+        'participant_id' => $paypalSummary['participant_id'],
+        'limit' => 100,
+    ]);
+    m4_service_assert_equal('ledger service paypal entry count', 2, count($paypalEntries), $failures, $passes);
+    foreach ($paypalEntries as $entry) {
+        m4_service_assert_equal('ledger service paypal entry tenant', $tenantId, $entry['tenant_id'], $failures, $passes);
+        m4_service_assert_equal('ledger service paypal entry participant', $paypalSummary['participant_id'], $entry['participant_id'], $failures, $passes);
+    }
+}
+
+$recentEntries = ledger_fetch_recent_entries($pdo, $tenantId, ['limit' => 5]);
+m4_service_assert_equal('ledger service recent entry limit', 5, count($recentEntries), $failures, $passes);
+$previousBookedAt = null;
+foreach ($recentEntries as $entry) {
+    m4_service_assert_equal('ledger service recent entry tenant', $tenantId, $entry['tenant_id'], $failures, $passes);
+    m4_service_assert('ledger service recent entry has amount', $entry['amount_cents'] !== 0, $failures, $passes);
+    if ($previousBookedAt !== null) {
+        m4_service_assert('ledger service recent entries are sorted', $previousBookedAt >= $entry['booked_at'], $failures, $passes);
+    }
+    $previousBookedAt = $entry['booked_at'];
+}
+
+$legacyConsumptionCount = (int)$pdo->query('SELECT COUNT(*) FROM kl_Kaffeeverbrauch')->fetchColumn();
+$consumptionEntries = ledger_fetch_recent_entries($pdo, $tenantId, [
+    'type' => 'consumption',
+    'limit' => 100,
+]);
+m4_service_assert_equal('ledger service consumption entry count', $legacyConsumptionCount, count($consumptionEntries), $failures, $passes);
+
+m4_service_assert_equal('ledger service empty participant id filter', [], ledger_fetch_participant_summaries($pdo, $tenantId, [
+    'participant_ids' => [],
+]), $failures, $passes);
+m4_service_assert_equal('ledger service unknown tenant summaries', [], ledger_fetch_participant_summaries($pdo, 0), $failures, $passes);
+m4_service_assert_equal('ledger service unknown tenant entries', [], ledger_fetch_recent_entries($pdo, 0), $failures, $passes);
+m4_service_assert_equal('ledger service unknown tenant totals', ledger_empty_totals(), ledger_fetch_tenant_totals($pdo, 0), $failures, $passes);
+
+if ($failures !== []) {
+    echo "\nM4 ledger service check failed with " . count($failures) . " failure(s):\n";
+    foreach ($failures as $failure) {
+        echo "- {$failure}\n";
+    }
+    exit(1);
+}
+
+echo "\nM4 ledger service check passed with {$passes} assertions.\n";