feat(db): add epc_property.source for predicted-EPC slot (ADR-0031)

Adds a `source` discriminator to `epc_property` so a property can hold a
lodged and a predicted EPC at the same time, per the EPC Prediction
production-wiring branch in the Model repo (docs/MIGRATION_NOTE_predicted_epc_source.md).

- `source` text NOT NULL default 'lodged' — backfills every existing row as
  a real lodged EPC.
- Unique index becomes (property_id, portfolio_id, source) so lodged +
  predicted rows can coexist for the same property/portfolio.
- New (property_id, source) index — lodged/predicted reads filter on both.

Allowed values: 'lodged' | 'predicted'.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/app/db/migrations/0234_old_rachel_grey.sql

@@ -0,0 +1,4 @@
+DROP INDEX "uq_epc_property_property_portfolio";--> statement-breakpoint
+ALTER TABLE "epc_property" ADD COLUMN "source" text DEFAULT 'lodged' NOT NULL;--> statement-breakpoint
+CREATE INDEX "ix_epc_property_property_source" ON "epc_property" USING btree ("property_id","source");--> statement-breakpoint
+CREATE UNIQUE INDEX "uq_epc_property_property_portfolio" ON "epc_property" USING btree ("property_id","portfolio_id","source");

src/app/db/migrations/meta/_journal.json

@@ -1632,6 +1632,13 @@
       "when": 1781513971818,
       "tag": "0233_abnormal_george_stacy",
       "breakpoints": true
+    },
+    {
+      "idx": 234,
+      "version": "7",
+      "when": 1781617412914,
+      "tag": "0234_old_rachel_grey",
+      "breakpoints": true
     }
   ]
 }

src/app/db/schema/property.ts

@@ -10,6 +10,7 @@ import {
   smallint,
   bigint,
   uniqueIndex,
+  index,
   jsonb,
 } from "drizzle-orm/pg-core";
 import { portfolio, PortfolioStatus } from "./portfolio";
@@ -428,6 +429,12 @@ export const epcProperty = pgTable(
       .unique()
       .references(() => uploadedFiles.id),
 
+    // Provenance of this EPC picture: "lodged" (a real public/landlord EPC) or
+    // "predicted" (EPC Prediction gap-fill, ADR-0031 in the Model repo). A
+    // property may hold one of each, so reads filter on it. Defaults to "lodged"
+    // — every existing row is a real lodged EPC.
+    source: text("source").notNull().default("lodged"),
+
     // Identity / admin
     uprn:                       bigint("uprn", { mode: "bigint" }),
     uprnSource:                 text("uprn_source"),
@@ -577,9 +584,17 @@ export const epcProperty = pgTable(
     ventilationMechanicalVentilationKind:  text("ventilation_mechanical_ventilation_kind"),
   },
   (table) => [
+    // A property may now hold one "lodged" and one "predicted" EPC row per
+    // portfolio (ADR-0031), so `source` is part of the uniqueness key.
     uniqueIndex("uq_epc_property_property_portfolio").on(
       table.propertyId,
       table.portfolioId,
+      table.source,
+    ),
+    // Every lodged/predicted read filters on (property_id, source).
+    index("ix_epc_property_property_source").on(
+      table.propertyId,
+      table.source,
     ),
   ],
 );