harden database interactions and improve error handling

drizzle/0001_hardening.sql

@@ -0,0 +1,11 @@
+ALTER TABLE `courses` ADD COLUMN `audit_status` text DEFAULT 'pending';
+--> statement-breakpoint
+ALTER TABLE `courses` ADD COLUMN `inference_warning` integer DEFAULT 0;
+--> statement-breakpoint
+CREATE UNIQUE INDEX IF NOT EXISTS `topics_course_order_unique` ON `topics` (`course_id`, `order`);
+--> statement-breakpoint
+CREATE UNIQUE INDEX IF NOT EXISTS `lessons_topic_unique` ON `lessons` (`topic_id`);
+--> statement-breakpoint
+CREATE UNIQUE INDEX IF NOT EXISTS `quiz_questions_topic_question_unique` ON `quiz_questions` (`topic_id`, `question`);
+--> statement-breakpoint
+CREATE UNIQUE INDEX IF NOT EXISTS `user_progress_course_topic_unique` ON `user_progress` (`course_id`, `topic_id`);

drizzle/meta/0001_snapshot.json

@@ -0,0 +1 @@
+{}

drizzle/meta/_journal.json

@@ -8,6 +8,13 @@
       "when": 1777109155026,
       "tag": "0000_init",
       "breakpoints": true
+    },
+    {
+      "idx": 1,
+      "version": "6",
+      "when": 1777200000000,
+      "tag": "0001_hardening",
+      "breakpoints": true
     }
   ]
 }