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/shared/schemas/results/UserAggregateResult.schema.ts

@@ -25,6 +25,7 @@ export const UserAggregateResultSchema = z.object({  _count: z.object({
     cloudFiles: z.number(),
     communications: z.number(),
     twilioSettings: z.number(),
+    telnyxSettings: z.number(),
     aiSettings: z.number(),
     officeHours: z.number(),
     officeContact: z.number(),