Make WebRTC serving reusable across demos

[jarcherNV]

Add shared WebRTC runtime and data-channel message contracts, plus common packaged-app and CUDA/distributed bootstrap helpers. Migrate the LingBot and OmniDreams WebRTC servers onto the shared helpers while keeping their model-specific routes, runtime config, and preflight logic local.

[greptile-apps]

Greptile Summary

This PR moves reusable WebRTC serving behavior into the shared FlashDreams package. The main changes are:

• Shared runtime, lifecycle, and data-channel message contracts.
• Common CUDA, distributed bootstrap, and packaged-app helpers.
• LingBot and OmniDreams migrations to the shared serving layer.
• Updated serving documentation and tests.

Confidence Score: 5/5

This looks safe to merge.

• The shared session runtime now includes the lifecycle methods used by the manager.
• Both migrated runtimes provide the required shutdown coordination.
• No blocking issue remains in the reviewed changes.

Important Files Changed

Filename	Overview
flashdreams/flashdreams/serving/webrtc/runtime.py	Defines shared generation, configuration, event, and distributed lifecycle contracts.
flashdreams/flashdreams/serving/webrtc/manager.py	Makes the shared session manager generic over the complete runtime and configuration contracts.
flashdreams/flashdreams/serving/webrtc/bootstrap.py	Centralizes CUDA initialization, distributed setup, logging, and server lifecycle coordination.
flashdreams/flashdreams/serving/webrtc/server.py	Adds a reusable app factory that keeps packaged browser resources alive through cleanup.
integrations/lingbot/lingbot/webrtc/server.py	Migrates LingBot app creation and distributed initialization to the shared helpers.
integrations/omnidreams/omnidreams/webrtc/server.py	Migrates OmniDreams app creation and distributed initialization to the shared helpers.

_{Reviews (3): Last reviewed commit: "Normalize WebRTC import ordering" | Re-trigger Greptile}

[gtong-nv]

LGTM