Migrating v2 plugins to v3 and recovering failures

Move legacy v2 plugin responsibilities to independent API 3 contracts and redesign activation, discovery, settings, backup and restore.

Plugin System v3 is a clean break: old v2 code is not loaded. One-time user-data migration is not runtime compatibility. Back up config, plugin data and archives; authors reimplement against the independent SDK.

Responsibility mapping

v2 interface/hook	v3 responsibility
Initialize, GetSettingsDefinitions	ActivateAsync + static typed settings
TryDiscoverManagedFolders, ConfigAugmenter	Discovery/ConfigReconciliation drafts and revision proposals
OnBeforeBackupFolder, BackupPreparationProvider	FilePolicy/BackupScope/BackupConsistency
OnAfterBackupFolder archive edits	ArtifactTransformer transaction; read-only CompletionObserver
OnBeforeRestoreFolder, OnAfterRestoreFolder	RestoreCoordinator/RestoreStagingPreparation; Host writes targets
HotkeyProvider	PluginCommandDescriptor
ParameterizedKnotLinkCommandHandler, CapabilityProvider	KnotLinkIntegration + optional TargetResolver

IFolderRewindPlugin keeps its name but changes methods. Remove Host DLL/Models references, string settings and path-based state ownership. Static services/capabilities must match registration.

User upgrades

The Host can migrate legacy MineRewind data offline using the bundled v3 package, retaining intent and typed state. Old flat payloads enter recoverable legacy quarantine without execution/deletion. Other v2 plugins require new author-provided packages; renaming ZIP to frplugin is insufficient.

Recovery

Corrupt config enters Recovery Center: preserve diagnostics/original files and use controlled recovery. --safe-mode suppresses code without rewriting Enabled Intent. Let startup journals recover interrupted migration/uninstall; never delete config.json/quarantine/history wholesale.

Verify identities, state, settings, runtime health and restores before restarting automation. RecoveryRequired blocks destructive operations until resolved.