⚡ Bolt: [performance improvement] Optimize GuildManager LoginListener notifications

[acsoto]

💡 What: Replaced the O(N*M) loop checking all online players with an O(M) loop that directly iterates over the guild member list and uses Bukkit.getPlayerExact() to retrieve the player objects in constant time.
🎯 Why: When a non-chairman logs in, the LoginListener iterated over the entire list of Bukkit.getOnlinePlayers() (O(N)), and fetched the guild member list for every single player to do a string .contains() check (O(M)). As player count increases, this creates significant main-thread latency during logins.
📊 Impact: Reduces time complexity from O(N * M) to O(M), significantly decreasing main-thread load on high-population servers. Also prevents redundant getGuildMembers() cache queries.
🔬 Measurement: A server profiler (like spark/timings) would show reduced cpu usage for LoginListener.onAuth during login events when player counts scale. Ensure login functionality correctly broadcasts to guild members only.

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PR created automatically by Jules for task 15211424017188027604 started by @acsoto

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