ENG-2985: WebRTC Phase 0 - Update publisher and playback examples

[felipeMoran-wowza]

Summary

This PR bundles all the work to adapt the WebRTC client examples to the new WebRTC reimplementation in Wowza Streaming Engine. The legacy examples are kept untouched but moved to v1/, and the new ones live in v2/, React-only (the jQuery variant was discontinued for the new version).

Repo reorganization

• The previous implementation was moved as-is to v1/src/ (jQuery + React).
• The new examples were rewritten from scratch in v2/src/react-example/.
• The handshake with WSE carries ?webrtcImplementation=v2 on the WebSocket URL so the server picks the new flow (see startPublish.js:214 and startPlay.js:255).

Key differences between v1 and v2

Signaling protocol. In v1, messages were a single nested payload with direction, command, streamInfo, sdp, and userData. v2 flattens and formalizes this: every message declares a messageType (OFFER / CANDIDATE) and an action (PUBLISH / VIEW), and the stream fields (applicationName, streamName, connectionId) live at the root. The status field in responses moved from status to statusCode.

ICE trickle. In v1, iceCandidates were bundled with the SDP in the server response. v2 implements real trickle ICE: candidates are sent as they're gathered in standalone CANDIDATE messages, with a queue (pendingCandidates) holding them until the server returns the connectionId so they can be associated. Same on the receive side for server-side candidates.

Configurable RTCPeerConnection. In v1, the peer connection was created with a bare new RTCPeerConnection() and no config. v2 accepts STUN and TURN servers configurable from the UI (IceServersUtils.js), with support for multiple comma-separated URLs and TURN credentials.

No more SDP munging. v1 had to hand-edit the SDP to force bitrates and codecs (v1/.../mungeSDP.js). That file is gone in v2: negotiation runs directly on the SDP the browser produces.

WHIP / WHEP. Added support for WHIP (publish) and WHEP (playback) as alternatives to WebSocket signaling, with trickle ICE over PATCH application/trickle-ice-sdpfrag (see startPublishWhip and startPlayWhep).

Other v2 tweaks.

• Centralized validation in ValidationUtils.js.
• Better error handling in publish/play (includes retries with backoff for 504/514 from the repeater).
• A fresh WebSocket is created for every play session (the old one was reused and caused issues on stop+play).
• Cookies to persist publish form values.
• Composite and Meeting tabs temporarily commented out from the nav until they're ready on the new server.

Included tickets

• ENG-3354 — signaling command updates.
• ENG-3388 — ICE trickle support.
• ENG-3209 / ENG-3210 — WHIP / WHEP.
• ENG-3387 — error handling, validation, and stop/play fixes.
• ENG-3486 — webrtcImplementation flag changes from modern to v2.
• ENG-3488 — final v1/v2 folder split.
• ENG-3531 — STUN harvester.
• ENG-3537 — fix for empty connectionId on candidates.
• ENG-3527 — hide Composite/Meeting tabs.
• ENG-3580 — configurable STUN/TURN fields in the forms.