Rename product blueprint URL param slug → product_slug

The app-level url_value_preprocessor pops "slug" and "page_slug"
into g.post_slug, with page_slug overwriting the product slug.
Renaming the blueprint param to product_slug eliminates the
collision entirely. Views now use g.product_slug (set by blueprint
preprocessor) and have clean signatures with no **_kw hacks.

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

bp/product/routes.py

@@ -22,20 +22,12 @@ from .services.product_operations import toggle_product_like, massage_full_produ
 
 
 def register():
-    bp = Blueprint("product", __name__, url_prefix="/product/<slug>")
+    bp = Blueprint("product", __name__, url_prefix="/product/<product_slug>")
     @bp.url_value_preprocessor
-    def pull_blog(endpoint, values):
-      # App-level preprocessor pops both "slug" and "page_slug" into g.post_slug,
-      # with page_slug overwriting slug. We need the original product slug which
-      # the app preprocessor popped first — but it's gone. Instead, extract the
-      # product slug from the request path: .../product/<slug>/...
-      from quart import request as req
-      parts = req.path.rstrip("/").split("/")
-      try:
-          idx = parts.index("product")
-          g.product_slug = parts[idx + 1] if idx + 1 < len(parts) else None
-      except (ValueError, IndexError):
-          g.product_slug = None
+    def pull_product_slug(endpoint, values):
+      # product_slug is distinct from the app-level "slug"/"page_slug" params,
+      # so it won't be popped by the app-level preprocessor in app.py.
+      g.product_slug = values.pop("product_slug", None)
 
     # ─────────────────────────────────────────────────────────────
     # BEFORE REQUEST: Slug or numeric ID resolver
@@ -71,7 +63,7 @@ def register():
             if not is_post:
                 canon = canonical_html_slug(product["slug"])
                 return redirect(
-                    host_url(url_for("market.browse.product.product_detail", slug=canon))
+                    host_url(url_for("market.browse.product.product_detail", product_slug=canon))
                 )
 
             g.item_data = {"d": product, "slug": product["slug"], "liked": False}
@@ -84,7 +76,7 @@ def register():
         canon = canonical_html_slug(raw_slug)
         if canon != raw_slug and not is_post:
             return redirect(
-                host_url(url_for("market.browse.product.product_detail", slug=canon))
+                host_url(url_for("market.browse.product.product_detail", product_slug=canon))
             )
 
         # hydrate full product
@@ -111,7 +103,7 @@ def register():
     # ─────────────────────────────────────────────────────────────
     @bp.get("/")
     @cache_page(tag="browse")
-    async def product_detail(slug: str):
+    async def product_detail():
         from shared.browser.app.utils.htmx import is_htmx_request
 
         # Determine which template to use based on request type
@@ -126,9 +118,8 @@ def register():
 
     @bp.post("/like/toggle/")
     @clear_cache(tag="browse", tag_scope="user")
-    async def like_toggle(slug):
-      # Use slug from URL parameter (set by url_prefix="/product/<slug>")
-      product_slug = slug
+    async def like_toggle():
+      product_slug = g.product_slug
 
       if not g.user:
           html = await render_template(
@@ -157,7 +148,7 @@ def register():
 
 
     @bp.get("/admin/")
-    async def admin(slug: str):
+    async def admin():
       from shared.browser.app.utils.htmx import is_htmx_request
 
       if not is_htmx_request():
@@ -177,7 +168,7 @@ def register():
 
     @bp.post("/cart/")
     @clear_cache(tag="browse", tag_scope="user")
-    async def cart(**_kw):
+    async def cart():
         slug = g.product_slug
         # make sure product exists (we *allow* deleted_at != None later if you want)
         product_id = await g.s.scalar(