fix: T2A cooking works without a craft menu (#2693)

## Summary
With T2A packet crafting menus enabled (`t2aCraftMenus`, default for pre-UOTD eras), cooking did nothing. Double-clicking a Skillet set a target, and `T2ACraftSystem.ShowMenu` had no Cooking branch, so the target was accepted and silently dropped. Nothing else could cook either: the old RunUO "use food on a heat source" code was never hooked up and was removed in #1054.

T2A cooking never used a menu, so this restores the item-on-item / item-on-heat-source flow:

- **Per-item handling:** each ingredient (`CookableFood`, `Dough`, `SweetDough`, `SackFlour`, `BowlFlour`, `JarHoney`) implements `IT2ACombinable.TryCombine` and switches on the target. `T2ACooking` holds the shared target, water, combine and heat-timer helpers.
- **Heat source:** all `CookableFood` (raw meats, fish, eggs, unbaked pies/quiche/pizzas, cookie and cake mix), dough → bread loaf, sweet dough → muffins. One unit is used up at the start, then a 5 s timer; the Cooking check runs from `CookingLevel` to 100 (bread and muffins use `DefCooking`'s range). The food burns on failure or if the cook moves more than 3 tiles away.
- **Combinations:**
  - Open flour sack or bowl of flour + water → dough
  - Dough + pear / peach / apple / pumpkin / eggs / meat / sausage → the matching unbaked pie, quiche or pizza
  - Dough + honey → sweet dough
  - Sweet dough + honey → cookie mix
  - Flour + sweet dough → cake mix
  - The honey and flour + sweet dough recipes work in either direction.
- **Water:** water drinks (pitchers), buckets, barrels, tubs and trough add-ons, in the pack, in hand, or on the ground within 2 tiles and in line of sight.
- **Cooking tools are passive:** with T2A menus on, a tool whose system has no T2A menu (`T2ACraftSystem.HasMenu`) falls through to `ShowCraftMenu`, which does nothing under T2A. No dead target is left.

Behaviour with T2A menus off is unchanged.

## Follow-ups
- Static troughs/barrels and open water aren't water sources here or for pitcher filling (no static water ID list exists); to be fixed separately.
- Whether a bowl of flour returns an empty bowl is unconfirmed (`//TODO`).
- Cooking tools that must merely be in the pack for some recipes are not modelled yet.

## Testing
- `dotnet build`: 0 warnings, 0 errors
- New `T2ACookingTests`: flour + water, closed sack refused, dough + apple, honey in both directions, cookie mix, cake mix, wrong target consumes nothing, water in another player's pack refused
- Not covered: the heat timer (untested); not yet exercised in game

Projects/UOContent/Engines/Craft/T2A/T2ACraftSystem.cs

@@ -15,6 +15,12 @@ public static class T2ACraftSystem
     /// </summary>
     public static bool Enabled { get; set; }
 
+    public static bool HasMenu(CraftSystem system) =>
+        system == DefBlacksmithy.CraftSystem || system == DefAlchemy.CraftSystem ||
+        system == DefBowFletching.CraftSystem || system == DefCarpentry.CraftSystem ||
+        system == DefCartography.CraftSystem || system == DefInscription.CraftSystem ||
+        system == DefTailoring.CraftSystem || system == DefTinkering.CraftSystem;
+
     public static void ShowMenu(Mobile from, CraftSystem craftSystem, BaseTool tool, Item preTarget = null)
     {
         if (!Enabled)