feat(operations-reporting): plan station targets per cargo category

The OCC report plans a station lane per cargo type — Nagad–Mojo container
and Nagad–Mojo fertilizer are separate numbers — but a target's identity
was period + metric + dimension + dimensionKey, so the two collided on
one slot. `cargo_category` is now part of the row and of the uniqueness
check; it stays null for cargo_category and container_class targets,
whose dimensionKey already carries the category.

The config grid showed raw codes (VOLUME_TONS, cargo_category, a yard
code). The list read now sends readable twins alongside the stored codes,
which stay exactly as they are because the reports join on them — the
same shape YardDistancesService uses. Labels resolve per dimension rather
than from one merged map: CONTAINER_EXPORT exists in both vocabularies
and reads differently in each, and merging them gave every cargo-category
row the container-class wording.

apps/edr-freight-api/src/migrations/3590000000000-OperationsTargetCargoCategory.ts

@@ -0,0 +1,51 @@
+import { MigrationInterface, QueryRunner } from "typeorm";
+
+/**
+ * A station's plan is per station AND per cargo type, not per station.
+ *
+ * The OCC monthly report plans "Nagad–Mojo multimodal container 122,010 t" and
+ * "Nagad–Mojo fertilizer 18,000 t" as separate lines against the same station,
+ * which the single `dimension_key` column cannot express: a station-keyed target
+ * would apply the whole station's plan to each of its cargo types.
+ *
+ * `cargo_category` is nullable, so `cargo_category` and `container_class`
+ * targets are unaffected — they leave it null and stay keyed on
+ * `dimension_key` alone. The uniqueness index moves to include it, since
+ * (station, category) is now the slot.
+ */
+export class OperationsTargetCargoCategory3590000000000 implements MigrationInterface {
+  name = "OperationsTargetCargoCategory3590000000000";
+
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`
+      ALTER TABLE freight.operations_targets
+        ADD COLUMN IF NOT EXISTS cargo_category varchar(60);
+    `);
+
+    await queryRunner.query(`DROP INDEX IF EXISTS freight.ux_operations_targets_slot;`);
+
+    // COALESCE rather than a plain column list: a partial unique index treats
+    // NULLs as distinct, which would let the same category target be entered
+    // twice over.
+    await queryRunner.query(`
+      CREATE UNIQUE INDEX IF NOT EXISTS ux_operations_targets_slot
+        ON freight.operations_targets (
+          period_type, period_start, metric, dimension, dimension_key,
+          COALESCE(cargo_category, '')
+        )
+        WHERE deleted_at IS NULL;
+    `);
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`DROP INDEX IF EXISTS freight.ux_operations_targets_slot;`);
+    await queryRunner.query(`
+      CREATE UNIQUE INDEX IF NOT EXISTS ux_operations_targets_slot
+        ON freight.operations_targets (period_type, period_start, metric, dimension, dimension_key)
+        WHERE deleted_at IS NULL;
+    `);
+    await queryRunner.query(`
+      ALTER TABLE freight.operations_targets DROP COLUMN IF EXISTS cargo_category;
+    `);
+  }
+}