Create a repo-defined schedule in a project's tessl.json from a plain-language description, optionally authoring the repo-local skill it runs. Use when the user wants to schedule a skill to run on a recurring cadence ("run X every morning", "kick off the report nightly", "schedule this weekly"), set up a recurring launch run, or add a `schedules` block to tessl.json. The user describes the task, cadence, and environment in plain words; this skill chooses the most readable supported schedule format, adds and validates the entry, and explains what happens on push. Not for one-off runs (use `tessl launch`) or for moving an existing UI/CLI schedule into the file (use schedule-migrate).