prices: fold groceries and CS skins into one price tracker (/trackers/prices) with tabs

- tab registry in #lib/price-trackers (add a tab = route + entry + icon)
- groceries -> /trackers/prices/groceries (owner-only), CS prices -> /trackers/prices/cs (public)
- old /trackers/groceries/* and /projects/cs-prices/* redirect (301 GET, 308 POST) with query
- nav: one prices entry replaces groceries and skins; cyan price-tag icon

src/lib/projects.ts

@@ -448,11 +448,12 @@ const allTrackers: readonly (Tracker & { private: boolean })[] = [
 		private: true
 	},
 	{
-		name: 'groceries',
-		subtitle: 'supermarket products, favorites and prices per store',
-		href: '/trackers/groceries',
+		// One price tracker with a tab per thing (#lib/price-trackers): groceries (mine) and CS skins.
+		name: 'prices',
+		subtitle: 'prices across time: groceries per store and Counter-Strike skins',
+		href: '/trackers/prices',
 		external: false,
-		private: true
+		private: false
 	},
 	{
 		name: 'houses',
@@ -476,13 +477,6 @@ const allTrackers: readonly (Tracker & { private: boolean })[] = [
 		children: gameTrackers,
 		private: false
 	},
-	{
-		name: 'skins',
-		subtitle: 'Counter-Strike skin market prices across time',
-		href: '/projects/cs-prices',
-		external: false,
-		private: false
-	},
 	{
 		name: 'pets',
 		subtitle: 'animaldex: add neighborhood pets to the world map',