Add auto-generated account numbers and member numbers

6-digit random numbers generated on create, unique per company. Member
number column added to member table. Both displayed in UI tables.

packages/backend/src/db/migrations/meta/_journal.json

@@ -64,6 +64,13 @@
       "when": 1774702800000,
       "tag": "0008_member_primary_account",
       "breakpoints": true
+    },
+    {
+      "idx": 9,
+      "version": "7",
+      "when": 1774703400000,
+      "tag": "0009_member_number",
+      "breakpoints": true
     }
   ]
 }