feat: add migration for admin actions and role fields

Adds new tables and columns for admin functionality:

- Create admin_actions table for audit logging
- Create qso_changes table for sync job rollback support
- Add role column to users (default: 'user')
- Add is_admin column to users (default: false)

No data loss - uses ALTER TABLE with safe defaults.

Co-Authored-By: Claude <noreply@anthropic.com>

drizzle/0002_nervous_layla_miller.sql

@@ -0,0 +1,25 @@
+CREATE TABLE `admin_actions` (
+	`id` integer PRIMARY KEY AUTOINCREMENT NOT NULL,
+	`admin_id` integer NOT NULL,
+	`action_type` text NOT NULL,
+	`target_user_id` integer,
+	`details` text,
+	`created_at` integer NOT NULL,
+	FOREIGN KEY (`admin_id`) REFERENCES `users`(`id`) ON UPDATE no action ON DELETE no action,
+	FOREIGN KEY (`target_user_id`) REFERENCES `users`(`id`) ON UPDATE no action ON DELETE no action
+);
+--> statement-breakpoint
+CREATE TABLE `qso_changes` (
+	`id` integer PRIMARY KEY AUTOINCREMENT NOT NULL,
+	`job_id` integer NOT NULL,
+	`qso_id` integer,
+	`change_type` text NOT NULL,
+	`before_data` text,
+	`after_data` text,
+	`created_at` integer NOT NULL,
+	FOREIGN KEY (`job_id`) REFERENCES `sync_jobs`(`id`) ON UPDATE no action ON DELETE no action,
+	FOREIGN KEY (`qso_id`) REFERENCES `qsos`(`id`) ON UPDATE no action ON DELETE no action
+);
+--> statement-breakpoint
+ALTER TABLE `users` ADD `role` text DEFAULT 'user' NOT NULL;--> statement-breakpoint
+ALTER TABLE `users` ADD `is_admin` integer DEFAULT false NOT NULL;