feat(throwing): core gargoyle Throwing skill (SA) (#2510)

Supersedes #2376 (@jwvalentine). This is a reviewed, corrected, and scoped-down **Phase 1** of Joe Valentine's throwing implementation — his original commits are cherry-picked here with authorship preserved, plus a fix/scoping pass. Phase 1 lands only the **core gargoyle Throwing skill**; the incomplete content is excised for follow-up PRs (see below).

## What's included (core skill)
- `BaseThrown` combat mechanics on top of the existing skeleton: close-quarters penalty, below-min-range penalty, shield penalty, STR-scaled range, overthrow damage penalty.
- Base weapons: **Boomerang, Cyclone, SoulGlaive** (gargoyle-only), + blacksmith crafting (SA-gated).
- Two symmetric hooks on `BaseWeapon` (`ModifyHitChance`, new `ModifyDamage`) that are inert no-ops for every other weapon.

## Fixes over the original
- **Overthrow damage**: was dead code (the swing gate already guarantees you're within `MaxRange`, so the old `ComputeDamage` check never fired). Reimplemented as `finalDamage × 0.53` applied *after* all offensive bonuses via a new `ModifyDamage` hook, firing at the outer range ring.
- **`DefMaxRange`**: clamped to `[MinThrowRange, MaxThrowRange]` (uncapped before → e.g. range 13 at 200 Str) and guarded against a latent divide-by-zero.
- **Close-quarters mitigation** now uses `RawDex` (matches ServUO/OSI; deterministic under stat mods).
- **Return-throw timer** guarded against a deleted/unmapped thrower/target.
- Reverted the `MovingShot` change (it rebalanced archery — belongs in a separate PR).
- Kept only complex-logic tests (hit-chance/range/damage math); dropped property-value assertions.

## Excised for follow-up PRs (Phase 2/3)
7 named artifacts, the Into-the-Void quest + Agralem, GargishOutcast, the Bladeweaver vendor, and the SA loot tables — these were unwired/non-functional (loot never triggered, quest/creature never spawned) and will return properly wired. `StormCaller` also needs its missing Battle Lust, and the quest its correct void-creature target.

## Verification
- Build: 0 warnings / 0 errors.
- `UOContent.Tests`: **501/501** passing (the `ModifyDamage` hook causes zero regressions across all weapons).
- Full whole-branch review completed: no must-fix defects.

Projects/UOContent/Items/Weapons/BaseWeapon.cs

@@ -1357,6 +1357,8 @@ public abstract partial class BaseWeapon
 
         var chance = ourValue / (theirValue * 2.0) * 1.0 + (double)bonus / 100;
 
+        chance = ModifyHitChance(attacker, defender, chance);
+
         if (Core.AOS && chance < 0.02)
         {
             chance = 0.02;
@@ -1365,6 +1367,19 @@ public abstract partial class BaseWeapon
         return attacker.CheckSkill(atkSkill.SkillName, chance);
     }
 
+    /// <summary>
+    ///     Allows subclasses to modify the final hit chance before the dice roll.
+    ///     Called after all standard AOS bonuses are applied but before the 2% floor.
+    ///     Supports both additive adjustments (chance -= 0.12) and multiplicative ones (chance *= scalar).
+    /// </summary>
+    protected virtual double ModifyHitChance(Mobile attacker, Mobile defender, double chance) => chance;
+
+    /// <summary>
+    ///     Allows subclasses to modify the final post-bonus damage (e.g. range-based penalties)
+    ///     before defender mitigation is applied. Mirrors <see cref="ModifyHitChance" />.
+    /// </summary>
+    protected virtual int ModifyDamage(Mobile attacker, Mobile defender, int damage) => damage;
+
     public virtual TimeSpan GetDelay(Mobile m)
     {
         double speed = Speed;
@@ -1874,6 +1889,7 @@ public abstract partial class BaseWeapon
         percentageBonus = Math.Min(percentageBonus, 300);
 
         damage = AOS.Scale(damage, 100 + percentageBonus);
+        damage = ModifyDamage(attacker, defender, damage);
 
         var defLoc = new WorldLocation(defender);
         var bcAtt = attacker as BaseCreature;