修复丢失的api；重新规划api结构

app/api/v1/endpoints/network/demands.py

@@ -30,5 +30,26 @@ async def fastapi_set_demand_properties(
 ############################################################
 # water distribution 36.[Water Distribution]
 ############################################################
-# This section was empty in main.py, so skipping unless found elsewhere or needed.
-# If there are specific Water Distribution endpoints they should go here.
+@router.get("/calculatedemandtonodes/")
+async def fastapi_calculate_demand_to_nodes(
+    network: str, req: Request
+) -> dict[str, float]:
+    props = await req.json()
+    demand = props["demand"]
+    nodes = props["nodes"]
+    return calculate_demand_to_nodes(network, demand, nodes)
+
+@router.get("/calculatedemandtoregion/")
+async def fastapi_calculate_demand_to_region(
+    network: str, req: Request
+) -> dict[str, float]:
+    props = await req.json()
+    demand = props["demand"]
+    region = props["region"]
+    return calculate_demand_to_region(network, demand, region)
+
+@router.get("/calculatedemandtonetwork/")
+async def fastapi_calculate_demand_to_network(
+    network: str, demand: float
+) -> dict[str, float]:
+    return calculate_demand_to_network(network, demand)