feat(db): add object.fields jsonb column, read it into CatalogueObject

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

crates/db/Cargo.toml

@@ -15,3 +15,4 @@ serde_json.workspace = true
 [dev-dependencies]
 tokio.workspace = true
 time.workspace = true
+serde_json.workspace = true

crates/db/migrations/0005_object_fields.sql

@@ -0,0 +1,2 @@
+-- Flexible field values for a catalogue object, keyed by field-definition key.
+ALTER TABLE object ADD COLUMN fields JSONB NOT NULL DEFAULT '{}'::jsonb;

crates/db/src/catalog.rs

@@ -15,7 +15,7 @@ const ENTITY_TYPE: &str = "object";
 
 const OBJECT_COLUMNS: &str = "id, object_number, object_name, number_of_objects, \
      brief_description, current_location, current_owner, recorder, recording_date, \
-     visibility, created_at, updated_at";
+     visibility, fields, created_at, updated_at";
 
 /// Create an object and record a `created` audit entry, both on `conn`
 /// (pass a transaction connection `&mut *tx` so they commit atomically).
@@ -110,6 +110,7 @@ fn map_object(row: sqlx::postgres::PgRow) -> Result<CatalogueObject, sqlx::Error
         recorder: row.try_get("recorder")?,
         recording_date: row.try_get("recording_date")?,
         visibility,
+        fields: row.try_get("fields")?,
         created_at: row.try_get("created_at")?,
         updated_at: row.try_get("updated_at")?,
     })

crates/db/tests/catalog.rs

@@ -116,3 +116,16 @@ async fn object_with_date_and_all_none_optionals_round_trips(pool: PgPool) {
             .any(|c| c.field == "recording_date")
     );
 }
+
+#[sqlx::test]
+async fn new_object_has_empty_fields(pool: PgPool) {
+    let db = Db::from_pool(pool);
+    let mut tx = db.pool().begin().await.unwrap();
+    let id = catalog::create_object(&mut tx, AuditActor::System, &sample_input("LM-9"))
+        .await
+        .unwrap();
+    tx.commit().await.unwrap();
+
+    let obj = catalog::object_by_id(db.pool(), id).await.unwrap().unwrap();
+    assert_eq!(obj.fields, serde_json::json!({}));
+}

crates/db/tests/migrate.rs

@@ -71,3 +71,16 @@ async fn migrate_creates_field_definition_tables(pool: PgPool) {
         );
     }
 }
+
+#[sqlx::test]
+async fn migrate_adds_object_fields_column(pool: PgPool) {
+    let db = Db::from_pool(pool);
+    let exists: Option<bool> = sqlx::query_scalar(
+        "SELECT true FROM information_schema.columns \
+         WHERE table_name = 'object' AND column_name = 'fields'",
+    )
+    .fetch_optional(db.pool())
+    .await
+    .unwrap();
+    assert_eq!(exists, Some(true));
+}

crates/domain/src/object.rs

@@ -62,6 +62,8 @@ pub struct CatalogueObject {
     pub recorder: Option<String>,
     pub recording_date: Option<Date>,
     pub visibility: Visibility,
+    /// Flexible field values (field key -> value), validated against the registry.
+    pub fields: serde_json::Value,
     pub created_at: OffsetDateTime,
     pub updated_at: OffsetDateTime,
 }