refactor(B1): migrate to domain-driven project structure

Move all models/schemas/services/routers into app/domains/.
Keep backward-compat shims in old locations for imports.
Preserves domains/rendering/tasks.py from Phase A.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/services/product_service.py

@@ -1,143 +1,15 @@
-"""Product service — lookup/create products, link CAD files."""
-import uuid
-from sqlalchemy import select, func, update as sql_update
-from sqlalchemy.ext.asyncio import AsyncSession
-
-from app.models.product import Product
-
-# Default render positions added to every newly created product.
-DEFAULT_RENDER_POSITIONS = [
-    {"name": "3/4 Front", "rotation_x": -15.0, "rotation_y":  45.0, "rotation_z": 0.0, "is_default": True,  "sort_order": 0},
-    {"name": "3/4 Rear",  "rotation_x": -15.0, "rotation_y": -135.0, "rotation_z": 0.0, "is_default": False, "sort_order": 1},
-    {"name": "Default",   "rotation_x":   0.0, "rotation_y":   0.0, "rotation_z": 0.0, "is_default": False, "sort_order": 2},
+# Compat shim — use app.domains.products.service instead
+from app.domains.products.service import (
+    create_default_positions,
+    lookup_product,
+    lookup_or_create_product,
+    link_cad_to_product,
+    DEFAULT_RENDER_POSITIONS,
+)
+__all__ = [
+    "create_default_positions",
+    "lookup_product",
+    "lookup_or_create_product",
+    "link_cad_to_product",
+    "DEFAULT_RENDER_POSITIONS",
 ]
-
-
-async def create_default_positions(db: AsyncSession, product_id: uuid.UUID) -> None:
-    """Insert the default render positions for a newly created product."""
-    from app.models.render_position import ProductRenderPosition
-    for pos_data in DEFAULT_RENDER_POSITIONS:
-        db.add(ProductRenderPosition(product_id=product_id, **pos_data))
-    await db.flush()
-
-
-def _fill_missing_fields(product: Product, pim_id: str | None, fields: dict) -> None:
-    """Fill in null/empty fields on an existing product without overwriting manual edits."""
-    if pim_id and not product.pim_id:
-        product.pim_id = pim_id
-    for attr in (
-        "name", "category_key", "ebene1", "ebene2", "baureihe",
-        "lagertyp", "name_cad_modell", "arbeitspaket",
-    ):
-        if fields.get(attr) and not getattr(product, attr, None):
-            setattr(product, attr, fields[attr])
-    # Update medias_rendering if not set
-    if fields.get("medias_rendering") is not None and product.medias_rendering is None:
-        product.medias_rendering = fields["medias_rendering"]
-    # Always update components from the latest Excel import (needed for auto-reassign)
-    if fields.get("components"):
-        product.components = fields["components"]
-
-
-async def lookup_product(
-    db: AsyncSession, pim_id: str | None, produkt_baureihe: str | None
-) -> Product | None:
-    """Read-only lookup: produkt_baureihe (primary), then pim_id (fallback).
-
-    Same cascade as lookup_or_create_product but never creates or mutates.
-    """
-    if produkt_baureihe:
-        result = await db.execute(
-            select(Product).where(
-                func.lower(Product.produkt_baureihe) == produkt_baureihe.lower(),
-                Product.is_active.is_(True),
-            )
-        )
-        product = result.scalar_one_or_none()
-        if product is not None:
-            return product
-        # baureihe provided but not found — skip pim_id fallback (same logic)
-        return None
-
-    if pim_id:
-        result = await db.execute(
-            select(Product).where(Product.pim_id == pim_id, Product.is_active.is_(True))
-        )
-        return result.scalar_one_or_none()
-
-    return None
-
-
-
-async def lookup_or_create_product(
-    db: AsyncSession, pim_id: str | None, fields: dict
-) -> tuple[Product, bool]:
-    """Look up by produkt_baureihe (primary), then pim_id (fallback). Create if not found.
-
-    Returns (product, was_created).
-    Does NOT overwrite existing fields — preserves manual edits.
-    """
-    produkt_baureihe = fields.get("produkt_baureihe")
-
-    # Primary lookup: by produkt_baureihe (case-insensitive)
-    if produkt_baureihe:
-        result = await db.execute(
-            select(Product).where(
-                func.lower(Product.produkt_baureihe) == produkt_baureihe.lower(),
-                Product.is_active.is_(True),
-            )
-        )
-        product = result.scalar_one_or_none()
-        if product is not None:
-            _fill_missing_fields(product, pim_id, fields)
-            await db.flush()
-            return product, False
-        # produkt_baureihe was provided but not found — each baureihe is a
-        # distinct product, so skip the pim_id fallback and create a new one.
-
-    # Fallback lookup: by pim_id (only when produkt_baureihe is absent,
-    # e.g. old per-category Excel files that don't have a Baureihe column).
-    if not produkt_baureihe and pim_id:
-        result = await db.execute(
-            select(Product).where(Product.pim_id == pim_id, Product.is_active.is_(True))
-        )
-        product = result.scalar_one_or_none()
-        if product is not None:
-            _fill_missing_fields(product, pim_id, fields)
-            await db.flush()
-            return product, False
-
-    product = Product(
-        pim_id=pim_id or f"auto-{uuid.uuid4().hex[:8]}",
-        name=fields.get("name"),
-        category_key=fields.get("category_key"),
-        ebene1=fields.get("ebene1"),
-        ebene2=fields.get("ebene2"),
-        baureihe=fields.get("baureihe"),
-        produkt_baureihe=produkt_baureihe,
-        lagertyp=fields.get("lagertyp"),
-        name_cad_modell=fields.get("name_cad_modell"),
-        arbeitspaket=fields.get("arbeitspaket"),
-        components=fields.get("components", []),
-        cad_part_materials=fields.get("cad_part_materials", []),
-        source_excel=fields.get("source_excel"),
-    )
-    db.add(product)
-    await db.flush()
-    await create_default_positions(db, product.id)
-    return product, True
-
-
-
-async def link_cad_to_product(
-    db: AsyncSession, product_id: uuid.UUID, cad_file_id: uuid.UUID
-) -> Product:
-    """Set product.cad_file_id via direct SQL UPDATE."""
-    await db.execute(
-        sql_update(Product)
-        .where(Product.id == product_id)
-        .values(cad_file_id=cad_file_id)
-    )
-    await db.commit()
-    result = await db.execute(select(Product).where(Product.id == product_id))
-    return result.scalar_one()