[mcp-atlassian] Authentication bypass in HTTP transport: AtlassianOpaqueTokenVerifier accepts any non-empty token

Description mcp-atlassian deploys in two common patterns: Pattern A single-user, server-side credentials: operator sets JIRAUSERNAME + JIRAAPITOKEN or CONFLUENCEUSERNAME + CONFLUENCEAPITOKEN in environment variables. Server uses these to call Jira/Confluence. This is the documented quickstart...