refactor(backend)!: separate algorithm and data layers

Reorganize algorithm packages by business responsibility, move orchestration into services, and keep database access behind pooled repositories.

Harden analysis API validation, remove unsafe legacy simulation endpoints, and add regression and architecture boundary coverage.

BREAKING CHANGE: legacy algorithm module paths and obsolete simulation endpoints are removed.

app/api/v1/endpoints/sensor_placement.py

@@ -7,10 +7,6 @@ from fastapi import APIRouter, Depends, HTTPException, Path, Query, status
 from fastapi.responses import StreamingResponse
 from starlette.concurrency import run_in_threadpool
 
-from app.algorithms.sensor import (
-    pressure_sensor_placement_kmeans,
-    pressure_sensor_placement_sensitivity,
-)
 from app.auth.metadata_dependencies import get_current_metadata_user
 from app.auth.project_dependencies import (
     ProjectContext,
@@ -34,6 +30,8 @@ from app.services.sensor_placement import (
     get_sensor_placement_candidate,
     get_sensor_placement_run,
     list_sensor_placement_runs,
+    optimize_sensor_placement_by_kmeans,
+    optimize_sensor_placement_by_sensitivity,
     update_sensor_placement_run,
 )
 
@@ -136,18 +134,18 @@ async def optimize_sensor_placement_scheme(
     network = _project_network(payload.network, project_context)
     _require_project_write(project_context)
     optimizer = (
-        pressure_sensor_placement_sensitivity
+        optimize_sensor_placement_by_sensitivity
         if payload.method == "sensitivity"
-        else pressure_sensor_placement_kmeans
+        else optimize_sensor_placement_by_kmeans
     )
     try:
         created = await run_in_threadpool(
             optimizer,
-            name=network,
-            scheme_name=payload.run_name,
-            sensor_number=payload.sensor_count,
+            project_code=network,
+            run_name=payload.run_name,
+            sensor_count=payload.sensor_count,
             min_diameter=payload.min_diameter,
-            username=current_user.username,
+            created_by=current_user.username,
         )
         run = get_sensor_placement_run(network, created["run_id"])
         return {**run, "can_edit": True}