fix(migrations): correct migration version from v4.0-to-v4.1 to v4.1-to-v4.2

The migration was incorrectly named as v4.0→v4.1 but was actually performing
the v4.1→v4.2 migration (moving thresholds from UPS-level to action-level).
This meant users upgrading from v4.1 would not get their configs migrated.

Changes:
- Renamed migration file from migration-v4.0-to-v4.1.ts to migration-v4.1-to-v4.2.ts
- Updated class name from MigrationV4_0ToV4_1 to MigrationV4_1ToV4_2
- Updated fromVersion from '4.0' to '4.1'
- Updated toVersion from '4.1' to '4.2'
- Updated shouldRun() to check for config.version === '4.1'
- Updated all imports and exports to reference the new class name
- Updated comments and log messages to reflect v4.1→v4.2 migration

ts/migrations/migration-v4.1-to-v4.2.ts

@@ -0,0 +1,125 @@
+import { BaseMigration } from './base-migration.ts';
+import { logger } from '../logger.ts';
+
+/**
+ * Migration from v4.1 to v4.2
+ *
+ * Major changes:
+ * 1. Moves thresholds from UPS level to action level
+ * 2. Creates default shutdown action for UPS devices that had thresholds
+ * 3. Adds empty actions array to UPS devices without actions
+ * 4. Adds empty actions array to groups
+ *
+ * Transforms v4.1 format (with UPS-level thresholds):
+ * {
+ *   version: "4.1",
+ *   upsDevices: [
+ *     {
+ *       id: "ups-1",
+ *       name: "UPS 1",
+ *       snmp: {...},
+ *       thresholds: { battery: 60, runtime: 20 },  // UPS-level
+ *       groups: [],
+ *       actions: []
+ *     }
+ *   ]
+ * }
+ *
+ * To v4.2 format (with action-level thresholds):
+ * {
+ *   version: "4.2",
+ *   upsDevices: [
+ *     {
+ *       id: "ups-1",
+ *       name: "UPS 1",
+ *       snmp: {...},
+ *       groups: [],
+ *       actions: [  // Thresholds moved here
+ *         {
+ *           type: "shutdown",
+ *           thresholds: { battery: 60, runtime: 20 },
+ *           triggerMode: "onlyThresholds",
+ *           shutdownDelay: 5
+ *         }
+ *       ]
+ *     }
+ *   ]
+ * }
+ */
+export class MigrationV4_1ToV4_2 extends BaseMigration {
+  readonly fromVersion = '4.1';
+  readonly toVersion = '4.2';
+
+  async shouldRun(config: any): Promise<boolean> {
+    // Run if config is version 4.1
+    if (config.version === '4.1') {
+      return true;
+    }
+
+    // Also run if config has upsDevices with thresholds at UPS level (v4.1 format)
+    if (config.upsDevices && config.upsDevices.length > 0) {
+      const firstDevice = config.upsDevices[0];
+      // v4.1 has thresholds at UPS level, v4.2 has them in actions
+      return firstDevice.thresholds !== undefined;
+    }
+
+    return false;
+  }
+
+  async migrate(config: any): Promise<any> {
+    logger.info(`${this.getName()}: Migrating v4.1 config to v4.2 format...`);
+    logger.dim(`  - Moving thresholds from UPS level to action level`);
+    logger.dim(`  - Creating default shutdown actions from existing thresholds`);
+
+    // Migrate UPS devices
+    const migratedDevices = (config.upsDevices || []).map((device: any) => {
+      const migrated: any = {
+        id: device.id,
+        name: device.name,
+        snmp: device.snmp,
+        groups: device.groups || [],
+      };
+
+      // If device has thresholds at UPS level, convert to shutdown action
+      if (device.thresholds) {
+        migrated.actions = [
+          {
+            type: 'shutdown',
+            thresholds: {
+              battery: device.thresholds.battery,
+              runtime: device.thresholds.runtime,
+            },
+            triggerMode: 'onlyThresholds', // Preserve old behavior (only on threshold violation)
+            shutdownDelay: 5, // Default delay
+          },
+        ];
+        logger.dim(
+          `    → ${device.name}: Created shutdown action (battery: ${device.thresholds.battery}%, runtime: ${device.thresholds.runtime}min)`,
+        );
+      } else {
+        // No thresholds, just add empty actions array
+        migrated.actions = device.actions || [];
+      }
+
+      return migrated;
+    });
+
+    // Add actions to groups
+    const migratedGroups = (config.groups || []).map((group: any) => ({
+      ...group,
+      actions: group.actions || [],
+    }));
+
+    const result = {
+      version: this.toVersion,
+      upsDevices: migratedDevices,
+      groups: migratedGroups,
+      checkInterval: config.checkInterval || 30000,
+    };
+
+    logger.success(
+      `${this.getName()}: Migration complete (${migratedDevices.length} devices, ${migratedGroups.length} groups updated)`,
+    );
+    return result;
+  }
+}