Changes to Start a HyperAgent task

removed the enum value claude-sonnet-4-5 of the request property llm

added the new gpt-6-luna enum value to the request property llm

added subschema #4 to the sessionOptions/credentials/items request property oneOf list

added the new optional request property sessionOptions/credentials

added the new optional request property sessionOptions/proxyRoutes

added the new optional request property sessionOptions/webBotAuth

added the new optional request property sessionOptions/enableWebMcp

added the new claude-haiku-5-5 enum value to the request property llm

added the new gemini-3.8-flash enum value to the request property llm

added the new gemini-3.7-flash enum value to the request property llm

added the new us enum value to the request property sessionOptions/region

added the new claude-sonnet-5 enum value to the request property llm

added the new gpt-5.5 enum value to the request property llm

added the new gpt-5.6-luna enum value to the request property llm