docs: add sanity check queries for ClickHouse ingestion

- Add 6 verification queries in README
- Check tables exist, MV definition, row counts
- Display raw and parsed logs samples
- Add interpretation guide for troubleshooting

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

README.md

@@ -378,6 +378,65 @@ SELECT raw_json
 FROM mabase_prod.http_logs_raw;
 ```
 
+### Sanity checks - Vérification de l'ingestion
+
+Après avoir déployé le service, vérifiez que les données circulent correctement :
+
+```sql
+-- 1. Tables présentes
+SELECT
+    database,
+    table,
+    engine
+FROM system.tables
+WHERE database = currentDatabase()
+  AND table IN ('http_logs_raw', 'http_logs', 'mv_http_logs');
+
+-- 2. Définition de la vue matérialisée
+SHOW CREATE TABLE mv_http_logs;
+
+-- 3. Vérifier que les inserts bruts arrivent
+SELECT
+    count(*)  AS rows_raw,
+    min(ingest_time) AS min_ingest,
+    max(ingest_time) AS max_ingest
+FROM http_logs_raw;
+
+-- 4. Voir les derniers logs bruts
+SELECT
+    ingest_time,
+    raw_json
+FROM http_logs_raw
+ORDER BY ingest_time DESC
+LIMIT 5;
+
+-- 5. Vérifier que la MV alimente http_logs
+SELECT
+    count(*) AS rows_flat,
+    min(time) AS min_time,
+    max(time) AS max_time
+FROM http_logs;
+
+-- 6. Voir les derniers logs parsés
+SELECT
+    time,
+    src_ip,
+    dst_ip,
+    method,
+    host,
+    path,
+    header_user_agent,
+    tls_version,
+    ja4
+FROM http_logs
+ORDER BY time DESC
+LIMIT 10;
+```
+
+**Interprétation :**
+- Si `rows_raw` > 0 mais `rows_flat` = 0 : la vue matérialisée ne fonctionne pas (vérifiez les droits SELECT sur `http_logs_raw`)
+- Si les deux comptes sont > 0 : l'ingestion et le parsing fonctionnent correctement
+
 ## Tests
 
 ```bash