feat. add crontab explainer

[madhav2348]

Description

Implementing crontab explainer, while project already have crontab generator, this will provides a clear, human-readable sentence explaining the schedule (leveraging and extending the existing
humanize logic).

Fixes #32

Dependencies

NA

Future Improvements

NA

Mentions

@rishima17

Screenshots of relevant screens

Developer's checklist

• My PR follows the style guidelines of this project
• I have performed a self-check on my work

If changes are made in the code:

• I have followed the Coding Guidelines
• My changes in code generate no new warnings
• My changes are not breaking another fix/feature of the project
• I have added test cases to show that my feature works
• I have added relevant screenshots in my PR
• There are no UI/UX issues

[SyedFahad7]

Thanks for the contribution @madhav2348 . I really like the direction here. The Crontab Explainer is a useful addition and it complements the existing generator nicely. I’ve reviewed this as production level logic though, and I can’t approve it in its current state because there are correctness issues that could mislead users.

Here are the key points that need to be addressed:

1. Day of Month and Day of Week logic mismatch
   I noticed the explanation text treats day of month and day of week as OR when both are set, but the execution preview logic appears to use strict AND. That means the explanation and the calculated next run times can disagree. This is a critical correctness issue.

2. Next 5 executions preview is incomplete
   The search window is capped at around 10,000 minutes, which is roughly 7 days. That means monthly or yearly schedules may not reliably show 5 executions. The preview needs to work for all valid cron expressions, not just short interval ones.

3. Validation is too weak
   Right now the validation only checks that there are 5 fields. Invalid values, ranges, and malformed expressions can still pass as valid. We need stronger validation before calling an expression valid.

4. Step parsing is incorrect for some patterns
   Expressions like 1-10/2 are not handled correctly because the step logic assumes a numeric base. This can lead to incorrect schedule interpretation.

5. UTC vs Local preview requirement
   The issue mentioned preview based on UTC or Local context, but the implementation currently only renders local time using toLocaleString(). That requirement is only partially fulfilled.

6. UX issue with preview toggle
   If no executions are found, the preview section does not render at all, which hides the toggle. That creates a confusing user experience.

7. Logic duplication
   This seems to duplicate cron explanation logic instead of reusing or extending the existing humanize path from the generator. We should align with the project’s reuse pattern for maintainability.

The overall idea is good and the routing and metadata wiring look correct. But since this tool deals with schedule correctness, it needs to be reliable before merging.

Please address the above points and open a fresh PR once updated. I’ll review it again quickly once the fixes are in.

[madhav2348]

Sure , some valid points you have share ,
Thanks for the review,I'll update as suggested as soon as possible

[SyedFahad7]

Sure , some valid points you have share , Thanks for the review,I'll update as suggested as soon as possible

Please sync your PR branch with the latest develop before re-review.

Use rebase (preferred) instead of merging develop into your feature branch to keep history clean:

git fetch upstream
git rebase upstream/develop
Resolve conflicts, then run local checks (npm run lint and npm run build)
git push --force-with-lease origin
Notes:

No need to fix unrelated pre-existing warnings across the repo.
Do fix any errors introduced by your PR (especially in touched files).
Rebase rewrites only your PR branch history; it does not rewrite our develop branch.
Once updated, we’ll re-review quickly.

[SyedFahad7]

Thanks for the contribution @madhav2348 and for adding the Crontab Explainer feature.

However, this PR currently contains a very large number of commits and several merge commits from your branch history, which makes the diff difficult to review. We also recently merged additional changes into the develop branch.

To keep the repository history clean and make the review process manageable, please do the following:

1. Sync your branch with the latest develop using rebase instead of merge.
2. Clean up the commit history so that only the commits related to the Crontab Explainer feature remain.
3. Push the rebased branch and open a clean PR with a minimal and reviewable commit history.

Example workflow:

git fetch upstream
git rebase upstream/develop
resolve conflicts if any
git push --force-with-lease origin

For now, we will close this PR to keep the review queue clean. Please reopen or create a fresh PR once the branch has been rebased and cleaned up.

Looking forward to reviewing the updated PR.