SETTINGS-35: species $/bdft in Settings + taxonomy parent fix (#76)

Add Settings species pricing UI (children of Species grouper by slug,
never hardcoded ids). Map Woo REST parent→parent_id on taxonomy sync;
upsert categories so slab FKs survive re-sync. Tests: parent map, FK-safe
sync, TV-8 0.96×12.50→12.00, Playwright mock e2e. UAT verified on 5060.

backend/taxonomy.py

@@ -20,6 +20,23 @@ def _scoped_tags(tags: list[dict]) -> list[dict]:
     return [t for t in tags if t.get("name", "").startswith(("fig-", "feat-"))]
 
 
+def _normalize_category(c: dict) -> tuple:
+    """Map a Woo REST category row into woo_categories insert values.
+
+    WooCommerce REST v3 returns `parent` (0 = top-level). Older fixtures may
+    already use `parent_id`. Never invent ids — only store what the payload carries.
+    """
+    raw_parent = c.get("parent_id", c.get("parent"))
+    if raw_parent in (0, "0", None, ""):
+        parent_id = None
+    else:
+        parent_id = int(raw_parent)
+    woo_id = c.get("woo_id", c.get("id"))
+    if woo_id is not None:
+        woo_id = int(woo_id)
+    return (c["id"], c["name"], c["slug"], parent_id, woo_id)
+
+
 def _subset_hash(categories: list[dict], attributes: list[dict],
                  terms_by_attr: dict, scoped_tags: list[dict]) -> str:
     subset = {
@@ -40,14 +57,37 @@ def sync(client: WooClient, conn) -> dict:
     terms_by_attr = {a["id"]: client.get_attribute_terms(a["id"]) for a in attributes}
     scoped_tags = _scoped_tags(tags)
 
+    # Attributes/tags/terms are not referenced by slabs FKs — safe to rebuild.
     conn.execute("DELETE FROM woo_attribute_terms")
     conn.execute("DELETE FROM woo_attributes")
-    conn.execute("DELETE FROM woo_categories")
     conn.execute("DELETE FROM woo_tags")
-    conn.executemany(
-        "INSERT INTO woo_categories(id, name, slug, parent_id, woo_id) VALUES (?,?,?,?,?)",
-        [(c["id"], c["name"], c["slug"], c.get("parent_id"), c.get("woo_id")) for c in categories],
-    )
+
+    # Categories: upsert then drop stale rows. A full DELETE fails when slabs or
+    # pricing_rules still reference species_id (live UAT IntegrityError on test-woo).
+    cat_rows = [_normalize_category(c) for c in categories]
+    cat_ids = [r[0] for r in cat_rows]
+    for row in cat_rows:
+        conn.execute(
+            "INSERT INTO woo_categories(id, name, slug, parent_id, woo_id) VALUES (?,?,?,?,?) "
+            "ON CONFLICT(id) DO UPDATE SET "
+            "name=excluded.name, slug=excluded.slug, parent_id=excluded.parent_id, woo_id=excluded.woo_id",
+            row,
+        )
+    if cat_ids:
+        placeholders = ",".join("?" * len(cat_ids))
+        conn.execute(
+            f"DELETE FROM woo_categories WHERE id NOT IN ({placeholders}) "
+            "AND id NOT IN (SELECT species_id FROM slabs WHERE species_id IS NOT NULL) "
+            "AND id NOT IN (SELECT species_id FROM pricing_rules)",
+            cat_ids,
+        )
+    else:
+        conn.execute(
+            "DELETE FROM woo_categories "
+            "WHERE id NOT IN (SELECT species_id FROM slabs WHERE species_id IS NOT NULL) "
+            "AND id NOT IN (SELECT species_id FROM pricing_rules)"
+        )
+
     conn.executemany(
         "INSERT INTO woo_attributes(id, name, slug, woo_id) VALUES (?,?,?,?)",
         [(a["id"], a["name"], a["slug"], a.get("woo_id")) for a in attributes],