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/variants/input/Communication.input.ts

@@ -2,6 +2,7 @@ import * as z from 'zod';
 import { CommunicationChannelSchema } from '../../enums/CommunicationChannel.schema';
 import { CommunicationDirectionSchema } from '../../enums/CommunicationDirection.schema';
 import { CommunicationStatusSchema } from '../../enums/CommunicationStatus.schema';
+import { CommunicationProviderSchema } from '../../enums/CommunicationProvider.schema';
 // prettier-ignore
 export const CommunicationInputSchema = z.object({
     id: z.number().int(),
@@ -10,6 +11,7 @@ export const CommunicationInputSchema = z.object({
     channel: CommunicationChannelSchema,
     direction: CommunicationDirectionSchema,
     status: CommunicationStatusSchema,
+    provider: CommunicationProviderSchema,
     body: z.string().optional().nullable(),
     callDuration: z.number().int().optional().nullable(),
     twilioSid: z.string().optional().nullable(),