Add production-ready Graveyard death recovery

[remdui]

Summary

Adds Graveyard, a durable packet-only death recovery feature that replaces physical death-chest plugins without placing blocks or Bukkit entities in the world.

Packet-only rendering and interaction

• sends concrete PacketEvents PacketWrapper<?> instances, preventing the raw ByteBuf overload/cast failure;
• builds block-display, text-display, and INTERACTION metadata from unspawned Paper entity templates so metadata indexes match the running protocol;
• registers each virtual interaction hitbox in a generation-fenced server-side index;
• intercepts INTERACT_ENTITY before vanilla attempts to resolve the packet-only entity;
• accepts right-click INTERACT, right-click-at-position INTERACT_AT, and left-click ATTACK actions;
• cancels packets targeting Graveyard hitboxes and schedules the authoritative claim attempt on the Bukkit main thread;
• revalidates current viewer generation, visible state, claim status, owner, inventory scope, world, configured distance, line of sight, and database operation reservation;
• serializes both owner and grave operations, so duplicate main-hand/off-hand or repeated click packets cannot duplicate delivery;
• forgets viewer state on disconnect without writing destroy packets to a closing network channel.

Player-facing grave names

Graves use a stable command identifier:

<player>-<world>-yyyyMMdd-HHmmss-SSS

The identifier is lower-case, command-safe, bounded in length, and stable after relocation. The internal UUID remains the durable database and recovery identity.

Commands and lifecycle visibility

• only active, partial, orphaned-world, and pending-delivery graves appear in normal player lists and suggestions;
• completed, expired, corrupt, recovered, and purged graves are excluded from normal tracking, claiming, locating, and active admin completion;
• expired graves remain available only through explicit restore, purge, and historical inspection paths;
• purge immediately removes every runtime index, cache, tracker, and completion source;
• command execution revalidates current state rather than trusting stale suggestions.

Persistence

All tables use the PlayerData namespace:

• player_graveyard_graves
• player_graveyard_payloads
• player_graveyard_audit
• player_graveyard_leases

No compatibility or automatic migration path exists for the earlier unreleased unprefixed development tables.

Reliability and safety

• fsynced capture and claim journals before ownership-changing mutations;
• persisted player receipts and playerdata at the transfer boundary;
• checksummed, size-bounded, versioned item payloads with corruption quarantine;
• optimistic revisions, operation tokens, owner-level serialization, and database writer leases;
• plugin-active-time expiry so ordinary downtime does not consume grave lifetime;
• safe loaded-location placement without chunk generation or forced loading;
• partial claims retain overflow without dropping or overwriting items;
• completed-record retention preserves audit history and excludes corrupt or in-flight operations.

Startup log clarification

Hibernate database-information output and HHH000489: No JTA platform available are normal INFO-level diagnostics for the configured local JDBC transaction model. The ORM initialization, command registration, feature load, and lease-acquisition messages indicate successful initialization.

Validation

Final head 80b951365636dade6e2a0dfa37b143319fc20261:

• current with main (behind_by: 0);
• CI Checkstyle and script lint: passed;
• Java 25 Maven verify and JaCoCo gates: passed;
• bundled Paper boot and clean-shutdown acceptance: passed;
• virtual interaction action regression: passed for INTERACT, INTERACT_AT, and ATTACK;
• operator documentation matches the enforced click contract;
• no temporary workflow or .agent files;
• no unresolved review threads;
• pull request mergeable.