[sven-n]

Split out of #995 (the server-side part of Diego Amatte's "send skill requirements to the client" commit), without the client data packets.

Problem

LearnablesConsumeHandlerPlugIn only checked the item's own requirements. A player could therefore learn a skill they can't use, and the item was used up. The clearest case is the Orb of Summoning: the item has no energy requirement, but the skills of its levels do:

Orb	Skill	Skill energy requirement
+0	Summon Goblin	90
+1	Summon Stone Golem	170
…	…	…
+6	Summon Soldier	280

Change

• LearnablesConsumeHandlerPlugIn.CheckPreconditions now also requires the player to meet the Skill.Requirements of the skill the item teaches. It gets that skill through the existing virtual GetLearnableSkill, so the Summoning Orb's override (item level → skill) applies.
• The requirement check inside Player.TryConsumeForSkillAsync is extracted to Player.CompliesRequirements(Skill) and reused here, so the rule isn't duplicated.

Compared to the original commit, this leaves out the static LearnableSkillRequirements helper, which replaced the Summoning Orb's GetLearnableSkill override with an IsSummoningOrb check (rule 8), and ItemExtensions.GetRequiredAttribute. Both were only needed for the C2 F5 04/05 packets. Those packets have no consumer in the open source client yet and aren't part of this PR.

Testing

LearnablesConsumeHandlerPlugInTest:

• a scroll teaches its skill only if the player meets the skill's energy requirement, and is only used up in that case
• an Orb of Summoning +0/+1 requires the energy of skill 30/31

The two "not learned" cases fail without the change. dotnet test tests/MUnique.OpenMU.Tests: 1856/1856 passed.

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Generated by Claude Code