New zai-web web-session provider drives the free chat.z.ai consumer
chat UI via a pasted browser cookie, distinct from the existing
API-key zai/glm/glm-cn/glmt providers (api.z.ai). ZaiWebExecutor posts
to chat.z.ai/api/chat/completions with the cookie forwarded both as
Cookie and Authorization: Bearer <token>, and normalizes both z.ai's
internal delta_content/phase SSE envelope and a pass-through
OpenAI-shaped choices[].delta frame into standard chat-completion
chunks.
Registered in WEB_COOKIE_PROVIDERS, WEB_SESSION_CREDENTIAL_REQUIREMENTS,
the provider registry (GLM-4.6/4.5/4.5V models), the executor factory,
and tokenExtractionConfig.ts for in-app cookie capture.
