NPM: lecture registre status Modbus (reg 19) + colonne npm_status

- get_data_modbus_v3.py: requete Modbus separee pour lire le registre
  status (0x13) du NextPM apres les donnees. Stocke dans npm_status.
- create_db.py: ajout colonne npm_status (INTEGER DEFAULT 0) dans
  data_NPM + migration ALTER TABLE pour bases existantes.
- En cas d'erreur de lecture status, garde 0xFF (toutes erreurs).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

sqlite/create_db.py

@@ -67,10 +67,18 @@ CREATE TABLE IF NOT EXISTS data_NPM (
     PM25 REAL,
     PM10 REAL,
     temp_npm REAL,
-    hum_npm REAL
+    hum_npm REAL,
+    npm_status INTEGER DEFAULT 0
 )
 """)
 
+# Add npm_status column to existing databases (migration)
+try:
+    cursor.execute("ALTER TABLE data_NPM ADD COLUMN npm_status INTEGER DEFAULT 0")
+    print("Added npm_status column to data_NPM")
+except:
+    pass  # Column already exists
+
 # Create a table BME280
 cursor.execute("""
 CREATE TABLE IF NOT EXISTS data_BME280 (