feat: hourly HII/ThaiWater rainfall + backup water-level collection

Poll the open api-v3.thaiwater.net public endpoints (rain_24h,
waterlevel_load), filter to the Ping basin, and persist to new
hii_rain_stations/hii_rainfall and hii_wl_stations/hii_waterlevel tables
(auto-created; sqlite/postgresql/mysql). Water levels stay in their own
tables since HII reports m MSL from a different station set; rid_code
maps mirrors like ridhydro_P.1 to P.1 and offset_msl converts MSL to
gauge datum. Runs every scraping cycle in web-api and continuous modes
(hourly cadence even during 1-minute RID retry), one-shot via
--collect-hii; docs/DATA_SOURCES.md catalogs all probed endpoints.

src/web_api.py

@@ -118,6 +118,17 @@ async def lifespan(app: FastAPI):
     db_config = Config.get_database_config()
     app_state["scraper"] = EnhancedWaterMonitorScraper(db_config)
 
+    # Initialize HII/ThaiWater collector (rainfall + backup water level)
+    try:
+        from .hii_collector import create_collector_from_config
+
+        app_state["hii_collector"] = create_collector_from_config()
+        if app_state["hii_collector"]:
+            logger.info("HII collection enabled (Ping-basin rainfall + water level)")
+    except Exception as e:
+        app_state["hii_collector"] = None
+        logger.error(f"HII collector initialization failed: {e}")
+
     # Initialize health checks
     health_manager = HealthCheckManager()
     health_manager.add_check(DatabaseHealthCheck(app_state["scraper"].db_adapter))
@@ -220,6 +231,22 @@ async def background_scraping_task():
                         increment_counter("scraping_cycles_failed")
                         logger.error(f"Background scraping cycle failed: {e}")
 
+                    # HII rainfall/water-level snapshot (independent of RID cycle)
+                    hii_collector = app_state.get("hii_collector")
+                    if hii_collector:
+                        try:
+                            hii_counts = await asyncio.get_event_loop().run_in_executor(
+                                None, hii_collector.run_cycle
+                            )
+                            set_gauge(
+                                "hii_rainfall_rows_saved", hii_counts["rainfall"]
+                            )
+                            set_gauge(
+                                "hii_waterlevel_rows_saved", hii_counts["waterlevel"]
+                            )
+                        except Exception as e:
+                            logger.error(f"HII collection failed: {e}")
+
                 app_state["is_scraping"] = False
 
             # Calculate next run time