PYSEC-2026-3573 Flyto2 Core: LLM/API keys leak to an attacker-controlled base_url

Summary llm.chat reads the operator's provider key from the environment OPENAIAPIKEY, ANTHROPICAPIKEY, ... and sends it in the Authorization: Bearer header to baseurl, a parameter the caller controls. baseurl is only checked against the SSRF guard, and the guard allows any public host, so pointin...