Add Input Validation for Task Creation

[Abd-Standard]

Description

Currently, task creation relies primarily on frontend validation. Implement server-side validation to ensure required fields, acceptable reward ranges, and valid deadlines are enforced before processing requests.

Acceptance Criteria
Validate all required fields.
Reject invalid reward values.
Ensure deadlines are future dates.
Return meaningful validation errors.

[julianvillalba688]

Motivation & Relevant Experience:
I have extensive experience building robust backend APIs and implementing secure server-side validation layers. I specialize in crafting clean, defensive code that ensures bad data never hits the database or blockchain state, and I am highly familiar with handling structured, developer-friendly error payloads.

Proposed Approach:

Validation Layer Implementation: Implement a strict server-side validation schema (using a tool like Zod, Joi, or built-in framework validators, depending on the project's tech stack) to intercept incoming task creation payloads.

Enforcing Rules:

Required Fields: Ensure title, description, and metadata are present.

Reward Ranges: Add bounds checking to reject negative, zero, or excessively high rewards.

Deadlines: Enforce that the provided timestamp is structurally valid and explicitly set in the future relative to the server's time (date > Date.now()).

Error Normalization: Structure a meaningful error handling middleware or helper that maps validation failures into clean, descriptive JSON responses (e.g., standard 400 Bad Request with field-specific messaging) so the frontend can display them seamlessly.

Testing: Write comprehensive unit tests for the validator covering both happy paths and edge cases (e.g., past dates, malformed rewards).

I can pick this up immediately and submit a clean, fully-tested pull request within 24 hours.

[grantfox-oss]

🦊 GrantFox — @julianvillalba688 has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #66)
2. Your PR will be reviewed by the Core-Foundry maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign | FWC26 campaign!

@julianvillalba688's PR #116 was approved and merged by @Abd-Standard.

🏆 @julianvillalba688: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (271 total points). Track your full progress on GrantFox.

👏 Great work, @julianvillalba688! Keep contributing to Core-Foundry.