[FernandoCelmer]

Summary

• Add _fix_step() helper to convert */N to 0/N in all cron fields
• Apply to _crontab_to_aws in dotflow/cloud/aws/schedule.py
• Apply same fix to template/hooks/post_gen_project.py
• Update and add tests for step value conversion

Problem

AWS EventBridge does not support */N syntax in cron expressions. It requires start/step format (e.g. 0/5). The previous _crontab_to_aws passed */N through unchanged, generating invalid schedules that fail at deploy time.

Examples

Input (crontab)	Before (invalid)	After (valid)
*/5 * * * *	cron(*/5 * * * ? *)	cron(0/5 * * * ? *)
0 */6 * * *	cron(0 */6 * * ? *)	cron(0 0/6 * * ? *)
30 2 * * *	cron(30 2 * * ? *)	cron(30 2 * * ? *) (unchanged)

Test plan

• test_crontab_every_5_minutes — */5 → 0/5
• test_crontab_step_in_hours — */6 in hours → 0/6
• test_crontab_no_step_unchanged — fields without */ are not modified
• All 13 schedule tests pass

Closes #250