Merge 51b30de (more fancy features) into preupdate

Resolve README install URL to the git.k6n.net module path (matches go.mod
and the import examples); keep the cart-reservation additions. go mod tidy
promotes miniredis to a direct dep (used in tests).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

README.md

@@ -6,6 +6,8 @@ A Go library for managing inventory using Redis.
 
 - Get and update inventory quantities
 - Reserve inventory with atomic operations using Lua scripts
+- Temporary cart-based reservations with expiration to prevent overselling
+- Optimized available inventory calculation using maintained reservation totals
 - Listen to inventory changes via Redis pub/sub
 
 ## Installation
@@ -34,6 +36,30 @@ if err != nil {
 }
 ```
 
+For cart reservations:
+
+```go
+cartService, err := inventory.NewRedisCartReservationService(client)
+if err != nil {
+    log.Fatal(err)
+}
+
+// Reserve items for a cart with 10-minute TTL
+err = cartService.ReserveForCart(ctx, inventory.CartReserveRequest{
+    InventoryReference: &inventory.InventoryReference{SKU: "item1", LocationID: "warehouse1"},
+    CartID: "cart123",
+    Quantity: 2,
+    TTL: 10 * time.Minute,
+})
+
+// Get available inventory (accounting for reservations)
+available, err := cartService.GetAvailableInventory(ctx, "item1", "warehouse1")
+
+// Get reservation summary for an item
+summary, err := cartService.GetReservationSummary(ctx, "item1", "warehouse1")
+fmt.Printf("Reservations: %d, Next release: %v, Remaining: %d\n", summary.ReservationCount, summary.EarliestRelease, summary.RemainingItems)
+```
+
 ## Dependencies
 
 - Go 1.25.1 or later