Implement intercom-first CallWaveKit 0.4

[PetrShtuka]

Summary

• rebuild PJSIP 2.17 with Apple Network.framework TLS and IPv6 support, remove --disable-ssl, and add deterministic binary verification
• add TURN over UDP/TCP/TLS, automatic/IPv4-only/IPv6-only policy, remote-cancel handling, VoIP token invalidation, audio route/interruption events, diagnostics snapshots, periodic raw RTP statistics, and async cancellation
• add an IntercomDemo, DocC documentation, a Linphone migration guide, compatibility/security/roadmap documentation, issue templates, and the Major-ios field checklist

Context

The public API advertised TLS while the bundled PJSIP binary was built with --disable-ssl and IPv6 disabled. Remote push cancellation, audio-session recovery, route changes, and PushKit token invalidation also had no complete host-facing flow.

Validation

• 67 unit tests pass: 19 Objective-C reliability/registry tests and 48 Swift tests
• generic iOS device build succeeds
• strict Swift concurrency build succeeds
• pod lib lint CallWaveKit.podspec --skip-tests --platforms=ios succeeds without --allow-warnings
• the PJSIP verifier confirms architectures, iOS 15 minimum deployment target, Apple TLS backend, and IPv6 capability
• demo Swift sources, plist, and entitlements pass static validation

Release gates

This PR intentionally remains a draft. It does not create a tag, GitHub Release, or CocoaPods publication.

Before releasing 0.4.0:

• pass the real SIPp/Asterisk integration matrix, including REGISTER, INVITE response variants, BYE, DTMF, hold, TLS certificate rejection, SRTP, and TURN
• pass the Major-ios device/field checklist, including cold launch, locked screen, Wi-Fi/cellular switching, Bluetooth, interruptions, late INVITE, remote cancellation, and repeated calls
• upload PJSIP.xcframework.zip, SHA-256, SwiftPM checksum, licenses, and the build manifest to the GitHub Release, then switch Package.swift from the local binary target to that release asset
• verify the appropriate PJSIP licensing terms for the closed-source Majordom application