Hardcode is_incognito: true in the Perplexity request and remove the toggle surface: the incognito tool parameter, PI_PERPLEXITY_INCOGNITO env var, config file field, /perplexity-config prompt, and TUI status indicators. Config and resolveDefaultModel are now model-only. Supersedes the incognito portion of PR #4. Co-authored-by: Ivan Pereira <183991+ivanrvpereira@users.noreply.github.com>