refactor: rename database → storage

More semantically accurate: contains SQLite files, schema, fixtures, test data.
Updated all references in code, scripts, docs.

scripts/setup-dev.sh

@@ -35,10 +35,10 @@ else
 fi
 
 # Create test database if needed
-if [ ! -f "database/test.db" ]; then
+if [ ! -f "storage/test.db" ]; then
     echo ""
     echo "📊 Creating test database..."
-    sqlite3 database/test.db < database/schema.sql
+    sqlite3 storage/test.db < storage/schema.sql
     echo "✓ Created test database"
 fi