fix: add NOT NULL constraints to artist_library_crossreference FK columns

Junction table FK columns were nullable, which is meaningless for a
cross-reference and also defeats the unique index (NULL != NULL in SQL).

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: jakebromberg

shared/database/src/schema.ts

@@ -369,8 +369,8 @@ export type ArtistLibraryCrossreference = InferSelectModel<typeof artist_library
 export const artist_library_crossreference = wxyc_schema.table(
   'artist_library_crossreference',
   {
-    artist_id: integer('artist_id').references(() => artists.id),
-    library_id: integer('library_id').references(() => library.id),
+    artist_id: integer('artist_id').references(() => artists.id).notNull(),
+    library_id: integer('library_id').references(() => library.id).notNull(),
   },
   (table) => [uniqueIndex('library_id_artist_id').on(table.artist_id, table.library_id)]
 );

tests/unit/database/schema.crossref.test.ts

@@ -0,0 +1,36 @@
+import * as fs from 'fs';
+import * as path from 'path';
+
+const schemaSource = fs.readFileSync(
+  path.resolve(__dirname, '../../../shared/database/src/schema.ts'),
+  'utf-8'
+);
+
+function extractTableBlock(source: string, tableName: string): string {
+  const pattern = new RegExp(
+    `export const ${tableName}\\s*=\\s*wxyc_schema\\.table\\([\\s\\S]*?\\);`
+  );
+  const match = source.match(pattern);
+  if (!match) throw new Error(`Table "${tableName}" not found in schema.ts`);
+  return match[0];
+}
+
+describe('artist_library_crossreference schema', () => {
+  const block = extractTableBlock(schemaSource, 'artist_library_crossreference');
+
+  it('artist_id column has .notNull()', () => {
+    const artistIdLine = block
+      .split('\n')
+      .find((line) => line.includes("artist_id:") || line.includes("'artist_id'"));
+    expect(artistIdLine).toBeDefined();
+    expect(artistIdLine).toContain('.notNull()');
+  });
+
+  it('library_id column has .notNull()', () => {
+    const libraryIdLine = block
+      .split('\n')
+      .find((line) => line.includes("library_id:") || line.includes("'library_id'"));
+    expect(libraryIdLine).toBeDefined();
+    expect(libraryIdLine).toContain('.notNull()');
+  });
+});