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.

tests/unit/test_pressure_cleaning.py

@@ -4,7 +4,7 @@ import numpy as np
 import pandas as pd
 import pytest
 
-from app.algorithms.cleaning import pressure as pressure_cleaning
+from app.algorithms.scada_cleaning import pressure_series as pressure_cleaning
 
 
 DATA_DIR = Path(__file__).resolve().parents[3] / "data"