feat: make Product fully independent from MarketplaceProduct

- Add is_digital and product_type columns to Product model
- Remove is_digital/product_type properties that derived from MarketplaceProduct
- Update Create form with translation tabs, GTIN type, sale price, VAT rate, image
- Update Edit form to allow editing is_digital (remove disabled state)
- Add Availability field to Edit form
- Fix Detail page for directly created products (no marketplace source)
- Update vendor_product_service to handle new fields in create/update
- Add VendorProductCreate/Update schema fields for translations and is_digital
- Add unit tests for is_digital column and direct product creation
- Add integration tests for create/update API with new fields
- Create product-architecture.md documenting the independent copy pattern
- Add migration y3d4e5f6g7h8 for is_digital and product_type columns

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

alembic/versions/x2c3d4e5f6g7_make_marketplace_product_id_nullable.py

@@ -0,0 +1,43 @@
+# alembic/versions/x2c3d4e5f6g7_make_marketplace_product_id_nullable.py
+"""Make marketplace_product_id nullable for direct product creation.
+
+Revision ID: x2c3d4e5f6g7
+Revises: w1b2c3d4e5f6
+Create Date: 2026-01-06 23:15:00.000000
+
+"""
+
+from collections.abc import Sequence
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = "x2c3d4e5f6g7"
+down_revision: str = "w1b2c3d4e5f6"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    """Make marketplace_product_id nullable to allow direct product creation."""
+    # SQLite doesn't support ALTER COLUMN, so we need to recreate the table
+    # For SQLite, we use batch mode which handles this automatically
+    with op.batch_alter_table("products") as batch_op:
+        batch_op.alter_column(
+            "marketplace_product_id",
+            existing_type=sa.Integer(),
+            nullable=True,
+        )
+
+
+def downgrade() -> None:
+    """Revert marketplace_product_id to NOT NULL."""
+    # Note: This will fail if there are any NULL values in the column
+    with op.batch_alter_table("products") as batch_op:
+        batch_op.alter_column(
+            "marketplace_product_id",
+            existing_type=sa.Integer(),
+            nullable=False,
+        )

alembic/versions/y3d4e5f6g7h8_add_product_type_columns.py

@@ -0,0 +1,47 @@
+# alembic/versions/y3d4e5f6g7h8_add_product_type_columns.py
+"""Add is_digital and product_type columns to products table.
+
+Makes Product fully independent from MarketplaceProduct for product type info.
+
+Revision ID: y3d4e5f6g7h8
+Revises: x2c3d4e5f6g7
+Create Date: 2026-01-07 10:00:00.000000
+
+"""
+
+from collections.abc import Sequence
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = "y3d4e5f6g7h8"
+down_revision: str = "x2c3d4e5f6g7"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    """Add is_digital and product_type columns to products table."""
+    with op.batch_alter_table("products") as batch_op:
+        batch_op.add_column(
+            sa.Column("is_digital", sa.Boolean(), nullable=False, server_default="0")
+        )
+        batch_op.add_column(
+            sa.Column(
+                "product_type",
+                sa.String(20),
+                nullable=False,
+                server_default="physical",
+            )
+        )
+        batch_op.create_index("idx_product_is_digital", ["is_digital"])
+
+
+def downgrade() -> None:
+    """Remove is_digital and product_type columns."""
+    with op.batch_alter_table("products") as batch_op:
+        batch_op.drop_index("idx_product_is_digital")
+        batch_op.drop_column("product_type")
+        batch_op.drop_column("is_digital")