Add legacy VoteStreak migration, recurring flag, and admin migrate command

[BenCodez]

Motivation

• Add automatic support for migrating legacy VoteStreak config and per-user legacy progress into the new VoteStreaks format to avoid data loss when upgrading.
• Support one-time vs recurring streak rewards so definitions can either trigger once at N or every N completions.
• Provide an admin command to trigger manual migration and notify admins how many definitions were converted.

Description

• Introduce a recurring flag to VoteStreakDefinition with a new constructor overload and expose it via isRecurring() to control reward behavior.
• Update processing logic in VoteStreakHandler.processVoteForDefinition to reward either once at the interval (recurring=false) or repeatedly every interval (recurring=true).
• Implement legacy migration helpers in VoteStreakHandler: getLegacyStreakProgress, migrateLegacyProgressIfNeeded, and migrateLegacyConfigManually, plus legacy-loading logic in VoteStreakConfigLoader to convert VoteStreak -> VoteStreaks entries, create IDs, persist migrated sections, and register user data columns.
• Add an admin command handler (admin command MigrateVoteStreaks) in CommandLoader to run migrateLegacyConfigManually() and reload definitions with an informational message.
• Update SpecialRewards.yml example to include the Recurring option and documentation comment for the new behavior.
• Update unit tests in VoteStreakHandlerTest to cover migration of per-user legacy progress and the config-section migration, and adjust helper utilities for the new Recurring property and silent logger handling.

Testing

• Ran the updated unit test class VoteStreakHandlerTest which now includes processVote_migratesLegacyProgressIntoNewState and configLoader_migratesLegacyVoteStreakSection and all tests passed.
• Executed the test suite via the project test runner (mvn test), and the modified vote streak tests completed successfully.

---

Codex Task