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>

packages/db/prisma/migrations/20260903183731_add_telnyx_settings_and_communication_provider/migration.sql

@@ -0,0 +1,25 @@
+-- CreateEnum
+CREATE TYPE "CommunicationProvider" AS ENUM ('twilio', 'telnyx');
+
+-- AlterTable
+ALTER TABLE "communications" ADD COLUMN "provider" "CommunicationProvider" NOT NULL DEFAULT 'twilio';
+
+-- CreateTable
+CREATE TABLE "telnyx_settings" (
+    "id" SERIAL NOT NULL,
+    "userId" INTEGER NOT NULL,
+    "apiKey" TEXT NOT NULL,
+    "phoneNumber" TEXT NOT NULL,
+    "texmlApplicationId" TEXT,
+    "messagingProfileId" TEXT,
+    "webhookPublicKey" TEXT,
+    "greetingMessage" TEXT,
+
+    CONSTRAINT "telnyx_settings_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateIndex
+CREATE UNIQUE INDEX "telnyx_settings_userId_key" ON "telnyx_settings"("userId");
+
+-- AddForeignKey
+ALTER TABLE "telnyx_settings" ADD CONSTRAINT "telnyx_settings_userId_fkey" FOREIGN KEY ("userId") REFERENCES "User"("id") ON DELETE CASCADE ON UPDATE CASCADE;

packages/db/prisma/migrations/20260903185238_add_telnyx_account_sid/migration.sql

@@ -0,0 +1,2 @@
+-- AlterTable
+ALTER TABLE "telnyx_settings" ADD COLUMN "accountSid" TEXT;