Add browser Call Control dialer sample

[SpaceEggs]

What changed

• add a standalone TypeScript browser dialer under examples/web-dialer
• connect to a 3CX programmable DN with PBX URL, Client ID, and Key
• bridge browser microphone and speaker audio through 3CX 8 kHz PCM streams
• support outbound dialing, inbound RoutePoint calls, mute, hangup, timer, and local recent-call history
• add a virtual incoming-call ringing phase with accept/reject controls and ringback for the caller
• bound browser, WebSocket, and PBX audio queues to prevent latency growth
• synchronously clear microphone, PBX writer, ringtone, and speaker queues on hangup
• keep 3CX credentials in the local Node session without browser persistence
• add root workspace and README entry points

Why

This provides a minimal reference for building a browser calling client with the Call Control API without registering a SIP endpoint.

RoutePoint calls are already connected by the PBX, so the ringing phase is intentionally virtual: media is withheld until the browser user accepts the call.

Validation

• yarn workspace @3cx-examples/web-dialer build
• yarn build
• local HTTP and WebSocket protocol smoke tests
• real-browser rendering and accessibility snapshot

Notes

No live PBX credentials were available, so the final 3CX inbound/outbound media path still needs validation against a configured RoutePoint. The sample intentionally binds to localhost and documents the additional controls required before remote or production deployment.