feat(GRO-600): extend reminder scheduler to send SMS alongside email

- Add SMS opt-in fields to clients schema (smsOptIn, smsConsentDate, smsOptOutDate, smsConsentText)
- Add channel column to reminderLogs with per-channel idempotency
- Create SMS service with Telnyx SDK integration and E.164 validation
- Update reminders service to conditionally send SMS to opted-in clients
- Add TCPA opt-out text to SMS reminders
- Graceful degradation: catch SMS errors without blocking email
- Fix: use clients.phone instead of non-existent clients.phoneE164
- Update clients route to expose SMS fields in API
- Add telnyx dependency to API package
- Create database migration 0028_sms_reminders

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

packages/db/migrations/meta/_journal.json

@@ -197,6 +197,13 @@
       "when": 1775655267192,
       "tag": "0027_refunds",
       "breakpoints": true
+    },
+    {
+      "idx": 28,
+      "version": "7",
+      "when": 1775741667192,
+      "tag": "0028_sms_reminders",
+      "breakpoints": true
     }
   ]
 }