add nested entity effects+conditions (#42341)

* add nested effect

* add nested condition

* move api to the main systems and improve effect guidebook text gen

---------

Co-authored-by: deltanedas <@deltanedas:kde.org>

Content.Shared/EntityEffects/SharedEntityEffectsSystem.Nested.cs

@@ -0,0 +1,21 @@
+using Robust.Shared.Prototypes;
+
+namespace Content.Shared.EntityEffects;
+
+/// <summary>
+/// Entity effects API counterparts using <see cref="EntityEffectPrototype"/> instead of <see cref="EntityEffect"/>.
+// </summary>
+public sealed partial class SharedEntityEffectsSystem
+{
+    [Dependency] private readonly IPrototypeManager _proto = default!;
+
+    /// <summary>
+    /// <c>TryApplyEffect</c> overload using a <see cref="EntityEffectPrototype"/> instead of <see cref="EntityEffect"/>.
+    /// </summary>
+    public void TryApplyEffect(EntityUid target, [ForbidLiteral] ProtoId<EntityEffectPrototype> id, float scale = 1f, EntityUid? user = null)
+    {
+        var proto = _proto.Index(id);
+        if (_condition.TryConditions(target, proto.Conditions))
+            ApplyEffects(target, proto.Effects, scale, user);
+    }
+}