Add vote_goal placeholders

[hugoocoding]

No description provided.

[Copilot]

Pull request overview

Adds support for vote “goal” placeholders to the Bukkit PlaceholderAPI expansion, enabling display of the current vote goal target and progress fetched from the Azuriom API.

Changes:

• Introduces %azlink_vote_goal_target% and %azlink_vote_goal_progress% placeholders.
• Extends the vote API response model to include a goal object (target/progress).
• Wires goal parsing + placeholder evaluation into VotePlaceholderProvider.

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[Copilot]

The HTTP request completes on the async executor (HttpClient.request uses supplyAsync), but the thenAccept callback mutates shared state (voteSites/users/topVotes/goal) that is also read from placeholder evaluation on the server thread. This creates a real data-race risk (e.g., inconsistent reads or IndexOutOfBounds/visibility issues). Consider marshalling the state update back onto the Bukkit main thread (scheduler runTask) or swapping in immutable snapshots / concurrent collections for all shared fields (not just goal).

[Copilot]

goalPlaceholder returns "0" whenever goal is null, even if the requested sub-key is invalid (e.g., %azlink_vote_goal_typo% would yield 0 instead of returning null). This makes invalid placeholders harder to detect and is inconsistent with other placeholder handlers. Consider switching on parts[1] first and only returning "0" for the known keys (target/progress) when goal is missing, while still returning null for unknown keys.

Suggested change

	if (currentGoal == null) {
	return "0";
	}
	switch (parts[1]) {
	case "target":
	return Integer.toString(currentGoal.target);
	case "progress":
	return Integer.toString(currentGoal.progress);
	String key = parts.length > 1 ? parts[1] : "";
	switch (key) {
	case "target":
	return currentGoal != null ? Integer.toString(currentGoal.target) : "0";
	case "progress":
	return currentGoal != null ? Integer.toString(currentGoal.progress) : "0";