Unified Upgrade Command & Migration System

[paulkczw]

Replaces the two-step version download + version switch workflow with a single version upgrade command and introduces a database/file migration framework for safe cluster-wide version transitions.

Changes

Upgrade Command

• Removed version download and version switch subcommands
• Added version upgrade [channel] [version] — downloads, verifies, and installs in one step
• Safety confirmations (channel change, downgrade warnings) retained
• All references in checkupdate, downloaded, and Updater.kt startup messages updated

Cluster-Wide Upgrade

• version upgrade automatically upgrades all connected cluster nodes via ClusterUpgradePacket
• Each remote node downloads from GitHub independently and reports success/failure
• Live status overview with per-node animations (pending → downloading → upgraded/failed)
• Pre-upgrade node list and post-upgrade summary with cluster shutdown reminder
• 120s timeout for remote node responses

Migration Framework (migrations/ module)

• New Gradle subproject with Migration interface (version, type, up()/down())
• Two migration types:
  • DATABASE — shared Redis changes, executed once per cluster with distributed lock (cloud:migration-lock)
  • LOCAL — file/folder changes, executed on every node independently
• MigrationRegistry for explicit registration with version-range queries (supports upgrade + downgrade)
• MigrationRunner handles the full startup flow:
  • Reads cloud:schema-version from Redis, compares with JAR version
  • Acquires distributed lock for DB migrations (5min timeout)
  • Wait-state with 2s polling when another node holds the lock (10min timeout)
  • Tracks local migrations via .local-schema-version file

Auto-Upgrade on Version Mismatch

• On startup, if cloud:schema-version is ahead of the node's JAR version, the node automatically downloads the correct release, installs it, and shuts down for restart
• Migrations run before the node registers as connected — no inconsistent cluster state

Startup Flow (NodeService)

Updater.check() → cleanup old JARs, log available updates
MigrationRunner.run() → returns UpgradeRequired or Success
├─ UpgradeRequired → auto-download + switch + shutdown
└─ Success → DB migrations (with lock) + local migrations
nodeRepository.connect() → node registers as connected