docs: PRODUCT.md as PRD with milestones

docs/PRODUCT.md

@@ -1,8 +1,10 @@
-# Product
+# Product requirements
 
-Each slab is one unit and one listing.
+SlabUploader creates one WooCommerce listing per wood slab for Whidbey Wood Store.
 
-A listing is complete when it has:
+Each slab is one unit and one listing. Photos and metadata are the inventory record.
+
+## Complete listing
 
 - Inventory photo(s), uniform 3:4 transparent PNG
 - SKU, length, thickness, price
@@ -12,7 +14,7 @@ A listing is complete when it has:
 - Title, short title, description
 - Zero or more `feat-*` tags
 
-Categories, attributes, and `fig-*` / `feat-*` tags are the store filters. Measured values feed title and description templates.
+Store categories, attributes, and `fig-*` / `feat-*` tags are the filters. Measured values feed title and description templates.
 
 ## Decision rights
 
@@ -28,6 +30,14 @@ Categories, attributes, and `fig-*` / `feat-*` tags are the store filters. Measu
 
 ## Create
 
-- FastAPI is the Woo client. Store credentials stay on the server.
-- `SLAB-UAT-*` creates as draft.
-- Duplicate SKU blocks create.
+FastAPI is the Woo client. Store credentials stay on the server.
+`SLAB-UAT-*` creates as draft.
+Duplicate SKU blocks create.
+A listing can be created with inference off.
+
+## Milestones
+
+1. Capture — `docs/CAPTURE.md` (current increment)
+2. Review — remaining listing fields in the app
+3. Create — Woo draft for a practice SKU
+4. Assist — optional vision and generated copy on a working manual path