fix(GRO-981): restore journal entries and add DESC to indexes

- _journal.json: restore idx 28 (0028_sms_reminders), add idx 29
  (0029_db_indexes_constraints), renumber 0030_messaging to idx 30
  (was missing 0028 and 0029 entries — they were silently skipped)
- schema.ts: add .desc() to conversations.lastMessageAt and
  messages.createdAt indexes per spec
- 0030_messaging.sql: add DESC to both generated index statements

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/db/migrations/meta/_journal.json

@@ -198,9 +198,23 @@
       "tag": "0027_refunds",
       "breakpoints": true
     },
+    {
+      "idx": 28,
+      "version": "7",
+      "when": 1775741667192,
+      "tag": "0028_sms_reminders",
+      "breakpoints": true
+    },
     {
       "idx": 29,
       "version": "7",
+      "when": 1775784467192,
+      "tag": "0029_db_indexes_constraints",
+      "breakpoints": true
+    },
+    {
+      "idx": 30,
+      "version": "7",
       "when": 1775828067192,
       "tag": "0030_messaging",
       "breakpoints": true