Add WebRTC Foundation API (RTCPeerConnection Subset)

Proposal

Introduce a minimal WebRTC signaling-level API for scenarios that need peer connection primitives without full media complexity.

• Expose RTCPeerConnection constructor and core methods.
• Support createOffer, createAnswer, setLocalDescription, setRemoteDescription.
• Add basic ICE candidate flow abstractions.
  Technical Notes:
• Back media and transport behavior with a pluggable platform interface.
• Keep initial implementation no-op friendly but state-correct.
  Acceptance Criteria:
• Peer connection state transitions are testable and deterministic.
• SDP method calls return valid object shapes.
• API is usable by automation and script engines for signaling tests.
  Out of Scope:
• Real media capture, codecs, and device pipeline.
• Full SCTP/DataChannel reliability semantics in first pass.

Description

Add a WebRTC foundation subset centered on RTCPeerConnection signaling operations: createOffer, createAnswer, setLocalDescription, and setRemoteDescription, with minimal ICE abstractions.

Background

Many applications need signaling compatibility for tests and protocol integration, even when media pipelines are mocked. A subset-first approach provides value without full media stack complexity.

Specification

• WebRTC 1.0 (RTCPeerConnection): https://w3c.github.io/webrtc-pc/
• Scope limited to signaling-state correctness and interoperable object shapes

No repository file or test entry point is named. Start by reviewing the WebRTC 1.0 RTCPeerConnection specification and the repository structure for a suitable platform-interface extension point. Done means deterministic signaling-state transitions, valid SDP object shapes, and minimal ICE abstractions that support automation without media or full DataChannel semantics.