Unified config file with [server] (user-facing: port, dir, ttl, lang, etc.) and [internal] (constants: timeouts, buffer sizes, cert params, UI timings). Replaces both DEFAULTS dict and hardcoded constants. JS constants (toast_ms, progress_hide_ms) passed through CFG injection. Old share.conf no longer used. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>