[verified] feat: add live river dashboard

Add mapped river and ThaiWater sensor layers, PostgreSQL history charts, API endpoints, and dashboard tests.

src/postgres_history.py

@@ -0,0 +1,66 @@
+"""Read historical station measurements from PostgreSQL."""
+
+import datetime
+import os
+from typing import Dict, List, Optional
+
+from sqlalchemy import create_engine, text
+
+
+class PostgresHistory:
+    def __init__(self, connection_string: Optional[str] = None, engine=None):
+        connection_string = connection_string or os.getenv("POSTGRES_CONNECTION_STRING")
+        if engine is None and not connection_string:
+            raise RuntimeError("POSTGRES_CONNECTION_STRING is not configured")
+        self.engine = engine or create_engine(connection_string, pool_pre_ping=True)
+
+    def station_history(
+        self,
+        station_code: str,
+        start: datetime.datetime,
+        end: datetime.datetime,
+        limit: int = 2000,
+    ) -> List[Dict]:
+        if not 1 <= limit <= 5000:
+            raise ValueError("limit must be between 1 and 5000")
+        if start >= end:
+            raise ValueError("start must be before end")
+
+        query = text(
+            """
+            SELECT m.timestamp, s.station_code, m.water_level,
+                   m.discharge, m.discharge_percent
+            FROM water_measurements m
+            JOIN stations s ON m.station_id = s.id
+            WHERE s.station_code = :station_code
+              AND m.timestamp >= :start_time
+              AND m.timestamp <= :end_time
+            ORDER BY m.timestamp ASC
+            LIMIT :limit
+            """
+        )
+        with self.engine.connect() as connection:
+            rows = connection.execute(
+                query,
+                {
+                    "station_code": station_code,
+                    "start_time": start,
+                    "end_time": end,
+                    "limit": limit,
+                },
+            )
+            result = []
+            for row in rows:
+                timestamp = row[0]
+                if isinstance(timestamp, str):
+                    timestamp = datetime.datetime.fromisoformat(timestamp)
+                result.append(
+                    {
+                        "timestamp": timestamp,
+                        "station_code": row[1],
+                        "water_level": float(row[2]) if row[2] is not None else None,
+                        "discharge": float(row[3]) if row[3] is not None else None,
+                        "discharge_percent": float(row[4]) if row[4] is not None else None,
+                    }
+                )
+            return result