Make arena creation sessions recoverable

[GerwinVerkerk]

Describe your changes

Make arena creation sessions recoverable without restarting the server when the selection stick is lost or a session needs to be abandoned.

This change:

• adds /hg session cancel as a clear alias for the existing end_session action;
• adds /hg session wand to give another selection stick during an active session;
• gives the initial selection stick directly to the player's inventory, dropping it only when the inventory is full;
• keeps both recovery actions behind the existing hungergames.command.session permission;
• adds a configurable language message for the replacement stick.

The existing session state, arena validation, and finalization flow are unchanged.

Verification

• ./gradlew build
• git diff --check
• Build completed successfully against the repository's Paper 26.2 configuration.

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Target Minecraft Versions: all currently supported versions
Requirements: none
Related Issues: #113

Checklist before requesting a review

• I have read the contributing guidelines

Worked on by

• United Factions Manager