* schedule: add `paseo schedule update` to edit schedules in place
Editing a schedule today requires delete+recreate, losing run history
and the schedule id. This adds an additive RPC and CLI command that
patches name, prompt, cadence, new-agent target fields, max-runs, and
expires-in without touching runs or in-flight executions. nextRunAt is
recomputed only when the cadence actually changes.
* schedule(cli): share cadence flag parser between create and update
Both paths were turning --every/--cron into a ScheduleCadence with
near-identical code. Extract `parseCadenceFromFlags` so the literals
and the exclusivity check live in one place; create wraps it to
require a value, update lets it stay optional.
Interval schedules used to wait the full interval before their first run, which
made `--every 1d` feel broken for fresh schedules. Now `--every` fires
immediately on creation; `--cron` keeps waiting for the next slot. `--no-run-now`
and `--run-now` override the defaults, and the parser rejects redundant combos.
Adds `paseo schedule run-once <id>` to manually trigger a single run without
advancing cadence or recomputing completion. The new `runOnCreate` field and
`schedule/run-once` RPC are additive on the WebSocket schema.
