feat(modelling): cut plan→recommendation readers onto plan_id

Rewrite the three structurally-identical m2m-join readers
(portfolio_functions.aggregate_portfolio_recommendations,
Outputs.get_recommendations_from_db, export get_recommendations) to join
PlanModel directly via recommendation.plan_id, dropping the plan_recommendations
join and its now-unused import. The writers set plan_id (prior slice), so the
rows resolve. test_export pins the export reader through the cut (its fixtures
now set recommendation.plan_id). A portfolio_functions DB characterization test
lands with the scenario consolidation (which provides the full-parity scenario
table the aggregation writes to).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/Outputs.py

@@ -11,7 +11,6 @@ from backend.app.db.models.portfolio import PropertyModel, PropertyDetailsEpcMod
 from backend.app.db.models.recommendations import (
     Recommendation,
     PlanModel,
-    PlanRecommendations,
 )
 
 
@@ -124,20 +123,15 @@ class Outputs:
         return plans_data
 
     def get_recommendations_from_db(self, plan_ids):
-        # Get recommendations through PlanRecommendations for those plans and that are default
+        # Get default recommendations for those plans, linked by recommendation.plan_id
         recommendations_query = (
             self.session.query(Recommendation, PlanModel.scenario_id)
-            .join(
-                PlanRecommendations,
-                Recommendation.id == PlanRecommendations.recommendation_id,
-            )
             .join(
                 PlanModel,
-                PlanModel.id
-                == PlanRecommendations.plan_id,  # Join with Plan to access scenario_id
+                PlanModel.id == Recommendation.plan_id,  # access scenario_id
             )
             .filter(
-                PlanRecommendations.plan_id.in_(plan_ids),
+                Recommendation.plan_id.in_(plan_ids),
                 Recommendation.default == True,  # Filtering for default recommendations
             )
             .all()

backend/app/db/functions/portfolio_functions.py

@@ -1,7 +1,6 @@
 from sqlalchemy import func
 from backend.app.db.models.recommendations import (
     PlanModel,
-    PlanRecommendations,
     Recommendation,
     ScenarioModel,
 )
@@ -26,11 +25,7 @@ def aggregate_portfolio_recommendations(
             ),
             func.sum(Recommendation.energy_cost_savings).label("energy_cost_savings"),
         )
-        .join(
-            PlanRecommendations,
-            PlanRecommendations.recommendation_id == Recommendation.id,
-        )
-        .join(PlanModel, PlanModel.id == PlanRecommendations.plan_id)
+        .join(PlanModel, PlanModel.id == Recommendation.plan_id)
         .filter(
             PlanModel.portfolio_id == portfolio_id,
             PlanModel.scenario_id == scenario_id,

backend/export/property_scenarios/db_functions.py

@@ -8,7 +8,6 @@ from collections import defaultdict
 from backend.app.db.models.recommendations import (
     Recommendation,
     PlanModel,
-    PlanRecommendations,
     RecommendationMaterials,
 )
 from backend.app.db.models.portfolio import (
@@ -157,13 +156,9 @@ class DbMethods:
 
         stmt = (
             select(Recommendation, PlanModel.scenario_id, PlanModel.name)
-            .join(
-                PlanRecommendations,
-                Recommendation.id == PlanRecommendations.recommendation_id,
-            )
-            .join(PlanModel, PlanModel.id == PlanRecommendations.plan_id)
+            .join(PlanModel, PlanModel.id == Recommendation.plan_id)
             .where(
-                PlanRecommendations.plan_id.in_(plan_ids),
+                Recommendation.plan_id.in_(plan_ids),
                 Recommendation.default.is_(True),
                 Recommendation.already_installed.is_(False),
             )

backend/export/tests/test_export.py

@@ -171,13 +171,17 @@ def test_default_export_integration(db_session):
     # 5) Insert recommendation
     # ----------------------------------------
 
+    rec_to_plan = dict(
+        zip(plan_recs_df["recommendation_id"], plan_recs_df["plan_id"])
+    )
     recs = [
         Recommendation(
+            plan_id=rec_to_plan.get(row["id"]),
             **{
                 col: row[col]
                 for col in Recommendation.__table__.columns.keys()
-                if col in row
-            }
+                if col in row and col != "plan_id"
+            },
         )
         for _, row in recommendations_df.iterrows()
     ]
@@ -607,9 +611,11 @@ def test_solar_with_battery_example(db_session):
     # -------------------------------------------------
     recommendations_df.loc[0, "measure_type"] = "solar_pv"
 
+    rec_to_plan = dict(zip(plan_recs_df.recommendation_id, plan_recs_df.plan_id))
     for row in recommendations_df.itertuples(index=False):
         rec = Recommendation(
             id=row.id,
+            plan_id=rec_to_plan.get(row.id),
             property_id=row.property_id,
             measure_type=row.measure_type,
             estimated_cost=row.estimated_cost,