feat(db): migration 0005 — password nullable + auth_provider column

SQLite table-rebuild (drizzle 12-step pattern) making users_table.password
nullable and adding auth_provider (default 'local'). Existing users backfill
to 'local'. Registered in meta/_journal.json.

Authored By: Culpur Defense Inc.

src/server/database/migrations/0005_federated_users.sql

@@ -0,0 +1,21 @@
+PRAGMA foreign_keys=OFF;--> statement-breakpoint
+CREATE TABLE `__new_users_table` (
+	`id` integer PRIMARY KEY AUTOINCREMENT NOT NULL,
+	`username` text NOT NULL,
+	`password` text,
+	`auth_provider` text DEFAULT 'local' NOT NULL,
+	`email` text,
+	`name` text NOT NULL,
+	`role` integer NOT NULL,
+	`totp_key` text,
+	`totp_verified` integer NOT NULL,
+	`enabled` integer NOT NULL,
+	`created_at` text DEFAULT (CURRENT_TIMESTAMP) NOT NULL,
+	`updated_at` text DEFAULT (CURRENT_TIMESTAMP) NOT NULL
+);
+--> statement-breakpoint
+INSERT INTO `__new_users_table`("id", "username", "password", "auth_provider", "email", "name", "role", "totp_key", "totp_verified", "enabled", "created_at", "updated_at") SELECT "id", "username", "password", 'local', "email", "name", "role", "totp_key", "totp_verified", "enabled", "created_at", "updated_at" FROM `users_table`;--> statement-breakpoint
+DROP TABLE `users_table`;--> statement-breakpoint
+ALTER TABLE `__new_users_table` RENAME TO `users_table`;--> statement-breakpoint
+PRAGMA foreign_keys=ON;--> statement-breakpoint
+CREATE UNIQUE INDEX `users_table_username_unique` ON `users_table` (`username`);

src/server/database/migrations/meta/_journal.json

@@ -36,6 +36,13 @@
       "when": 1771352889394,
       "tag": "0004_optimal_mandrill",
       "breakpoints": true
+    },
+    {
+      "idx": 5,
+      "version": "6",
+      "when": 1784131200000,
+      "tag": "0005_federated_users",
+      "breakpoints": true
     }
   ]
 }