fix(config/ui): wire `min_tokens` from UI to runtime and fix NameError

• Replace undefined global_min_tokens with min_tokens in the Search path of generate_sync_data() (2 occurrences) to resolve NameError.
• In load_config(), include use_timeline and min_tokens in the globals and assign them from args.* so UI changes take effect at runtime.
• In write_config(), persist min_tokens when saving the default config (no payload).

Backwards-compatible with configs missing min_tokens (defaults to 0).