CVE-2026-27626: OliveTin: OS Command Injection via `password` argument type and webhook JSON extraction bypasses shell safety checks

OliveTin’s shell mode safety check (checkShellArgumentSafety) blocks several dangerous argument types but not password. A user supplying a password-typed argument can inject shell metacharacters that execute arbitrary OS commands. A second independent vector allows unauthenticated RCE via webhook-extracted JSON values that skip type safety checks entirely before reaching sh -c.