feat: migrate SMS/voice to Telnyx (TeXML), keep browser dial pad on Twilio

Twilio now handles only the in-browser dial pad (Access Token + browser-Device
outbound TwiML); Telnyx takes over SMS, inbound voicemail, the AI voice
conversation loop, and staff-triggered outbound calls via TeXML. Adds
TelnyxSettings model, Communication.provider discriminator, new comms/routes
modules, and a real Telnyx Settings page.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/Frontend/src/pages/settings-page.tsx

@@ -14,6 +14,7 @@ import { Staff } from "@repo/db/types";
 import { NpiProviderTable } from "@/components/settings/npiProviderTable";
 import { ProgramBridgeTable } from "@/components/settings/program-bridge-table";
 import { TwilioSettingsCard } from "@/components/settings/twilio-settings-card";
+import { TelnyxSettingsCard } from "@/components/settings/telnyx-settings-card";
 import { AiSettingsCard } from "@/components/settings/ai-settings-card";
 import { OfficeHoursCard } from "@/components/settings/office-hours-card";
 import { OfficeContactCard } from "@/components/settings/office-contact-card";
@@ -30,6 +31,7 @@ type SectionId =
   | "npi"
   | "programs"
   | "twilio"
+  | "telnyx"
   | "ai"
   | "aichat"
   | "officehours"
@@ -260,6 +262,9 @@ export default function SettingsPage() {
       case "twilio":
         return <TwilioSettingsCard />;
 
+      case "telnyx":
+        return <TelnyxSettingsCard />;
+
       case "ai":
         return <AiSettingsCard />;